The guinea pig, or cavy (from their Latin name Cavia porcellus), is a docile rodent native to the Andes Mountain Range area of South America. The Andean Indians of Peru first domesticated them. During the 18th century, Dutch explorers introduced guinea pigs to Europe, where fanciers selectively bred them. These pets are now bred in a variety of colours and hair lengths, including the hairless guinea pig: aptly called a 'skinny pig'. To this day, the guinea pig remains a favourite among children due to their docile behaviour, ease of handling and quiet nature. These medium sized rodents live on average 4-5 years.


Good quality food and fresh, clean water must be readily available at all times.
Diet Guinea pigs tend to be creatures of habit, and therefore do not tolerate changes in the presentation of their food or water or changes in the taste, odour, texture or form of the food itself. Pet owners should avoid making radical changes in the food or water containers as well. Any sudden change in routine can result in the pet refusing its food and water, which can be dangerous. If the diet you are presently feeding your guinea pig is very different from our recommendations, make changes gradually.
All foods should be provided in heavy ceramic crocks that resist both tipping and chewing. The crocks should be high enough to keep bedding and faecal pellets out of the food, but low enough for easy access by the animal.

Commercially available pellet chows provide all the essential nutrients required by guinea pigs, as long as they are fresh and of high quality. A good quality guinea pig pellet should be offered daily. Closely monitoring the quantity is key:

  • Young Guinea Pigs require more energy for their rapid growth and development and as such can be fed a "free-choice" (i.e. as much as they want) dish of growth formula pellets. These pellets are usually alfalfa based, with high fibre (20%) and low protein (18%).
  • Adult (over 6 months) and older guinea pigs should eat a timothy-based pellet. These pellets are designed with low protein (14%) and higher fibre content (28%).
    Skinny and Baldwin pigs may require a slightly higher caloric intake; however, unless your veterinarian advises you otherwise, a guideline for your adult guinea pig can be estimated by his weight:
    500 gr -1 kg body weight: Feed 1/8 cup per day
    1 kg - 2 kg body weight: Feed ¼ cup per day
DO NOT REFILL THE BOWL even if pellets are all eaten before the next day.
Our recommendations for pellet rations take into account age, weight and lifestyle. Their unrestricted use can result in a myriad of health problems including obesity with concurrent heart and liver disease, chronic diarrhoea, bladder stones and kidney disease.
These pellets contain approximately 800 mg of vitamin C per kilogram of ration. Do not feed rabbit pellets as a substitute for guinea pig pellets. They are not equivalent in nutritive value. Unlike rabbits, and most mammals for that matter, guinea pigs require a high level of folic acid and vitamin C. Guinea pig diets are uniquely formulated with these requirements in mind, whereas rabbit pellets are not.
Make sure any pellet you buy is fresh, preferably sold in a sealed bag with a best-before date on it. We do not recommend bulk bought pellets, as it is impossible to determine their freshness. Buy small quantities and keep it refrigerated or cool and dry to prevent spoilage. Old, rancid pellets may cause your guinea pig to stop eating. If you must buy more than a two-month supply at a time, freeze them.

Vitamin C
Unlike most mammals, guinea pigs cannot manufacture their own vitamin C; therefore, they must receive it from an outside source. Pellet guinea pig diets are supplemented with this essential vitamin. However, even when properly stored in a cool, dry place, fresh pellets lose about one-half of their vitamin C content due to degradation within six weeks of manufacture. For this reason, we also recommend further vitamin C supplementation in the water as follows: 50 milligrams ascorbic acid (human vitamin C syrup or powder or pills) added to 1 cup of drinking water, made up fresh every 12 hours. Chewable Guinea pig formulated Vitamin C tablets are also available on the market. Alternatively, your guinea pig can be offered fresh foods with high Vitamin C content such as fresh kale, cabbage or a quarter orange daily. High vitamin C content foods are noted below.

Timothy or Grass Hay
Hay is an essential part of your guinea pig's diet, and should be available at all times for constant grazing. The fibre in hay is extremely important in promoting normal digestion and in preventing gastro-intestinal stasis. Hay contains proteins and other nutrients essential for good health.
We prefer the loose, long strands of hay as opposed to the pressed cubes. Research of hay products has shown that some hay is superior to others. Try to buy 1st or 2nd cut hay products (i.e. the first grown and cut crop of the season), as they are richer in nutrients and have a superior overall quality. The kinds of hay available on the market are:

  • Timothy or Grass Hay: should be offered daily in unlimited amounts. This hay is usually 30% fibre and 10% protein.
  • Oat hay: very similar in nutrient value to timothy hay. You can interchange oat and timothy hay to provide some variety in your guinea pig's diet.
  • Alfalfa Hay: We no longer recommend the use of alfalfa hay, as it has been shown to be too high in calcium and carbohydrates, which may lead to serious health problems.

Fresh Vegetables and Fruits
We like guinea pigs to get greens and lots of them. Pick the dark coloured fibrous greens, which are rich in a variety of nutrients. Feed a minimum of 3 types daily to get your cavy used to variety. In this way, if changes have to be made, they are tolerated more easily.
ANY MAJOR CHANGE IN THE TYPES OF FOOD FED TO YOUR PET CAN LEAD TO SERIOUS DIGESTIVE UPSETS. Start with one food at a time, checking that each new addition is well tolerated, until you know what your guinea pig digests well. Once you establish your pet's routine, be consistent.


Give your pet a combination of a least 3 of the following, in a minimum total amount of 1 heaping cup per pound (500 grams) of body weight:
Red bell peppers* parsley * spinach or mustard greens* kale* broccoli leaves and stems* Brussels sprouts*, Dill*, turnip greens, spinach*, outer cabbage leaves, carrot tops, beet tops, dandelion greens (pesticide and herbicide free), curly lettuce, chicory, dark leaf lettuce, escarole, endive, radicchio, parsnip, wheat grass, carrot, green and other bell peppers, squash, clover, etc.
(*= Good source of vitamin C)
Avoid iceberg lettuce, starchy vegetables and legumes such beans, peas, corn, potatoes and sweet potatoes.


Fruit can be fed with a few restrictions. Offer 1/4 cup per pound (500 grams) of body weight daily. Feed high fibre fruits such as apples, oranges*, pears/peaches, papaya*, cantaloupe, guava* pineapple and strawberries*. Avoid sugary fruits such as bananas and grapes.

Grains such as oats, wheat, crackers, breakfast cereal, bread, pasta, etc. Completely avoid, nuts, salty or sugary snacks or chocolate.
Do not feed your guinea pig commercially sold 'treats'. These foods are typically high is sugars and fats and can to a variety of disease problems. Stick to fresh foods as a treat for your guinea pig.

Fresh water
Provide cool fresh water daily. Water is most easily made available by the use of a water bottle equipped with a "sipper" tube. Guinea pigs tend to contaminate and clog their water bottles by chewing on the end of the sipper tube and "backwashing" food particles into it. For this reason, it is imperative that all food and water containers be cleaned and disinfected daily. Be sure your guinea pig is used to his water container, and offer a separate dish if you are unsure he is drinking. Guinea pigs that eat large quantities of vegetables will drink less as they satisfy their water intake with these foods.


Generally, guinea pigs are docile, non-aggressive animals. They rarely bite or scratch when handled. They usually voice their protest simply by letting out a high-pitched squeal. They may, however, struggle when being picked up or restrained. Extreme care should be taken not to injure them during handling. The guinea pig should be approached with both hands. One hand is placed under the guinea pig's chest and abdomen, while the other hand supports its hindquarters. Adults, and especially pregnant females, should receive careful attention to gentle, yet firm and total support.

Living environment

Housing accommodations provided for pet guinea pigs are limited only by one's imagination, ingenuity, and budget. There is no single correct way to house your guinea pig as long as the wellbeing of your pet is considered.
Your guinea pig must be able to exercise every day, which can happen within a larger enclosure, or while roaming part of your home under careful supervision.

A minimum requirement for a guinea pig is a 24"wide by x 48" long by 18" high cage that provides little exercise, but is adequate when you are not at home. The cage can remain opened on the top if the sides are at least 10 inches high, as long as other family pets such as dogs, cats or ferrets are not a threat.

A corral (approximately 2 feet by 8 feet) can be used if the bars are close enough together to avoid escape. This solution provides much more room to move during the day, but does little to satisfy the curious nature of your pet. Be sure to allow your guinea pig to explore other areas of your house while you clean his corral, providing mental stimulus and exercise at the same time.

Cage flooring should be solid. We do not recommend any kind of mesh or wire flooring. Some people use wire mesh flooring, which they believe provides a cleaner environment and easier maintenance, but many result in injuries to the feet and hocks. Housing on wire often results in footpad and hock infections from abrasive rubbing on faecal soiled wire. As well, broken legs are common in guinea pigs that fall through the wire mesh and panic to escape. Instead, cage bottoms should be made of non-porous plastic. Avoid wood, glass, wire or other chewable materials. Wood should not be used on any part of the cage due to difficulty in cleaning and susceptibility to destructive gnawing. Gnawing also easily destroys many softer plastics.
Corrals made of stainless steel can be placed over ceramic, linoleum, cement or hardwood floors. Protect your floors with brown, white or newspaper that can be removed daily. We recommend using many layers of newspaper, brown paper or other paper. This way several layers can be rolled up daily in order to remove faecal pellets, urine, hair and uneaten fresh foods. Because paper can be a bit slippery for your pet, it is recommended to provide a soft skid-free surface in part of his cage, ideally where he spends most of his time. The easier your guinea pig's living space is to clean the better; we recommend daily cleaning of the cage substrate and all food dishes.

Hiding Spot
We strongly recommend hiding spots, as guinea pigs are nervous by nature, and may jump or panic if startled. They feel much more secure if provided with a place to hide. This can be easily accomplished by providing a cardboard box within the enclosure, with one side open, and all the other sides closed. Another solution is to provide your pet with a "hammock style" roof by threading a towel through half of his cage, so he can easily hide underneath it. The hiding spot is an ideal location to provide a softer floor surface.

Bedding materials must be clean, nontoxic, absorbent, relatively dust-free and easy to replace. Acceptable beddings include layers of paper, towels or blankets, shredded paper, or recycled newsprint litters such as "Care fresh" or "Yesterdays news".
Ground corncob is not recommended as it may harbour fungal spores, and can be eaten by your pet, causing digestive problems. Cedar and pine shavings have been associated with respiratory difficulty and liver disease in some guinea pigs and therefore should not be used. Saw dust should also be avoided since not only is it particularly dusty, bit it tends to accumulate within the external genitalia of male guinea pigs.
If you bed the entire floor of your guinea pigs cage with a recycled litter pellet, it may be hard to evaluate the quality and quantity of his stool and urine. As well, he may ingest particles of it when he eats his fresh foods. We recommend using recycled litters either in one corner of the cage or his litter box, but not throughout the entire enclosure. Consider using a litter box and trying to litter-train your guinea pig.

All dishes should be impermeable to water and easy to clean. Hard plastic, stainless steel or heavy ceramic bowls are ideal. Water can be provided via a water bottle or heavy bowl that is weighted or secured to the side of the cage so that it does not tip over. Beware of residue on the inside of water bottles- scrub them or run them through a dishwasher daily. Pellets and veggies can be offered in a bowl or plate. Hay can be spread on a clean area of the floor or offered in a wire basket that attaches to the side of the enclosure.

Location and environmental considerations
The environment in the vicinity of the pet's cage is another important consideration. Because of their sensitive nature, guinea pigs are more comfortable and relaxed when housed in a bright and quiet spot away from noise, excitement and other such stresses. Since they are nocturnal (active at night), guinea pigs require quiet periods during the day (when we are active around them) in order to rest.
Select a location away from direct sunlight and avoid cold damp areas. Guinea pigs thrive in a dry, cool environment with adequate ventilation. For this reason, we recommend a cage that is made of wire or plastic on at least three sides. Aquaria are not recommended.
Drastic environmental changes should be prevented, especially high temperatures and humidity. Guinea pigs are susceptible to heat stroke, so adopt some of these measures to keep your cavy cool during warm weather:

  • Provide a piece of linoleum or a ceramic tile in his or her enclosure to lie on
  • Keep fresh, cool water available at all times
  • Leave a plastic milk jug or pop bottle filled with frozen water in the cage as a portable "air conditioner"
  • Keep the cage out of direct sunlight
  • Keep the cage in the coolest room of the house
  • Provide a fan from outside the cage to circulate air
  • Change the drinking water 2 or 3 times a day to keep water cool
Since guinea pigs are social creatures, more than one animal may be safely housed together. Be sure to introduce new animals slowly, and your veterinarian has verified their health. In addition, males and females can remain in the same enclosure indefinitely. However, new males may occasionally fight if in the presence of a female. Older, dominant animals may also chew on the ears or hair of subordinate cage mates.

Medical Problems

The single most important consideration regarding guinea pig breeding is that the female guinea pig (sow) should be bred between four and seven months of age if she is to be bred at all. If the first breeding is delayed much beyond this time, serious, and often fatal problems with delivery may result. The reason for this is that the pelvis of the guinea pig fuses at this early age, which narrows the birth canal, preventing the babies from passing through easily, if at all. Males (boars) should be at least four months of age before breeding.
The sow's oestrus cycle ("heat") lasts 14 to 19 days. The actual period in which the sow is receptive to the boar for breeding is approximately eight to fifteen hours during this cycle. Sow's often return to 'heat" within a few hours after giving birth. This time is known as "postpartum oestrus" which means that she can be nursing one litter while being pregnant with another.
Pregnancy lasts between 63 to 70 days. The gestation period is shorter with larger litters, and longer with small litters. This duration of pregnancy is relatively long when compared to other rodents. Pregnant sows exhibit a grossly enlarged abdomen during the latter stages of pregnancy. Her body weight may actually double during pregnancy. The time of delivery is difficult to assess in guinea pigs due to the relatively long gestation period and lack of nest building by the sow. Within one week prior to delivery, a slight widening of the pelvic area can be noted. This is the separation of the pelvis, which if does not occur, can cause the delivery problems mentioned previously. If the pelvis does not separate, as in sows that are bred past seven months of age, delivery of the young may be impossible without a caesarean section.
An uncomplicated delivery usually takes about one-half hour with an average of five minutes between babies. Litter sizes range between one and six, with an average of three to four. First time litters are usually very small. Unfortunately, abortions and stillbirths are not uncommon with guinea pigs.
The young are very well developed at birth. They weigh between 50 and 100 grams and have a full hair coat. Babies are even born with teeth and with their eyes open. Mothers are not very maternal in the raising of the offspring; she does not build a nest and even remains in a sitting position while nursing. The young can eat solid food and drink from a bowl shortly after birth, but it is recommended to allow them to nurse for three weeks before weaning.

Slobbers, Dental Malocclusion
'Slobbers' is a condition where the fur under the jaw and down the neck remains wet from the constant drooling of saliva. The primary cause for this condition is overgrowth of the guinea pig's teeth, most often the premolars and/or molars. This occurs more frequently in older guinea pigs (2-3 years of age). The overgrowth is due to genetic factors that result in improper alignment of the teeth. An improper diet, including excess selenium, may also contribute to dental malocclusion.
Guinea pig teeth are constantly growing, which means that if improperly aligned, they do not wear down evenly. The overgrown piece of the tooth (that which is not being worn down) causes injury to the guinea pig's tongue or cheek, resulting in an inability or unwillingness to chew and swallow food. The tongue may also become trapped by inward growing teeth. This may or may not cause drooling down the chin and neck, but often results in severe weight loss, pain and mouth ulceration.
A veterinarian must be consulted as soon as this condition is suspected. The diagnosis is confirmed by visual examination of the mouth. While the owner can visualize overgrown incisors, molars need to be seen using a special lighted speculum called a laryngoscope. Treatment involves trimming or filing of the overgrown teeth. Dental work in the mouth of a guinea pig is difficult due to the extremely small mouth opening and must be attended to by a veterinarian with expertise in this field. Depending on the how serious the condition, recovery may involve painkillers until the mouth ulcers are healed, supplementation with fluid therapy, supplemental vitamins and force feedings. If GI stasis has occurred, hospitalizing your pet may be recommended.
This is no permanent solution or correction to molar malocclusion. Although misaligned incisors can be permanently removed by surgical means, this is not performed routinely. In other cases, periodic trimming or filing of the teeth is necessary depending on how quickly the teeth grow. A correction of the diet may also be recommended.
Guinea pigs with this problem should not be bred since dental malocclusion is often hereditary.

Gastro-intestinal (GI) Stasis
Fibre in a cavy's diet is responsible for proper gastro-intestinal motility (contractions of the stomach and intestine which move food down the system). Any factor that contributes to decreasing the proportion of fibre in the stomach or intestines will cause gastro-intestinal stasis (GIS). Excessive ingestion of fur is one of these factors. Other factors that can contribute to gastro-intestinal slowing include dental malocclusion (and thus reduced food consumption), heat stroke, antibiotic treatment, surgery, pain and dietary changes.
Guinea pig digestion is relatively slow and ingested material can remain in the stomach for more than 3 days. Ingested fur, especially during shedding periods, will accumulate in the stomach, which is a normal process, but sometimes, when the fur is not mixed with sufficient fibre and fluid, it can form a pasty clump. Guinea pigs do not have the ability to vomit, and so cannot bring up their stomach contents. If enough of this pasty clump accumulates, the stomach motility will slow down. Your pet feels his stomach is full and he will stop eating; this further slows digestion, which will eventually stop.
Initially the stools may appear clumped or they may be linked together with strands of fur. Eventually stool become smaller and smaller until they are not produced altogether.
Your pet may still be drinking, appear active and alert and lively for up to the first week of this condition, even if he is not eating. Don't be deceived: he has a serious condition and you should seek medical attention immediately. If tended to early, your cavy can be treated medically and the stasis resolved. If the condition is allowed to progress, long hospital stays and, occasionally, surgery will be necessary to alleviate the problem. This condition can be fatal so seek help early on.
A complete examination including x-rays and a dental exam will be suggested to find the underlying cause of this condition to avoid its recurrence. Treatment may include a combination of force feedings, fluids, painkillers and gastro intestinal stimulants.
The best prevention of gastro-intestinal stasis is a diet high in fibre and daily brushing, especially during shedding periods, with a wire "slicker" type brush. You can also offer papaya tablets one to two times daily to help break up the fur.
Other preventative measures include careful monitoring of dietary and environmental changes, providing sufficient daily exercise outside of his cage, and keeping a watchful eye on stool production in order to catch any GI changes early on.

Scurvy (Vitamin C deficiency)
Guinea pigs, like humans and other primates, cannot manufacture Vitamin C and must receive an adequate supply from outside food sources. Lack of sufficient Vitamin C in the diet results in scurvy. Adult guinea pigs require approximately 15 mg a day; pregnant sows require at least 30-40 mg per day.
The symptoms of scurvy include poor appetite; swollen, painful joints and ribs; reluctance to move; poor bone and teeth development, rough hair coat, lack of appetite, and spontaneous bleeding, especially from the gums. If left untreated this disease can be fatal, especially to rapidly growing young guinea pigs and pregnant females. In addition, sub clinical deficiencies often predispose animals to other diseases.
The mandatory level of vitamin C is supplemented in commercial guinea pig pellet rations. However, with improper storage and handling these pellets lose their potency rapidly. In fact, even when properly stored in a cool, dry environment, fresh pellets lose up to half of their potency in approximately six weeks due to degradation of the vitamin. For this reason, further supplementation is recommended.
Contact a veterinarian at the first sign of this condition for early diagnosis and treatment. These animals must be treated early with supplemental vitamin C (given in food, water or by injection) in order to reverse the symptoms.

Uroliths (Bladder stones)
Guinea pigs are susceptible to bladder problems that include making mineral rich sandy urine and bladder stones. Symptoms of bladder stones usually begin by noting a change in urine colour moving from clear to reddish or containing minerals that have crystallized. Sometimes your guinea pig stops urinating all together. Although the cause of bladder stones is unclear, diet and water consumption may be contributing factors.
Diagnosing bladder stones involves a complete exam, urinalysis and x-ray. Treatment depends on the size and location of the stones, but may involve radical diet changes, antibiotics, anti-inflammatories or painkillers and ultimately, surgery to remove the stones.
Since this is a painful and progressive condition, consult your veterinarian as soon as possible.

Barbering (Hair Chewing)
Hair loss is a common problem in guinea pigs. "Barbering" may be one of the reasons. This bad habit occurs when guinea pigs chew on the hair coats of other guinea pigs that are lower than them in the social "pecking order." His or her normal full hair coat identifies the dominant cavy, and main culprit, while others have areas of alopecia (hair loss). Carefully introducing new cage mates may help avoid this problem. Some pet owners also have success by offering sufficient amounts of hay all day such that the offending guinea pig has something else to chew on. Offering a larger living space can also reduce barbering. If these measures do not work, separating out the problem guinea pig may be necessary if it becomes a serious problem.
Hair loss or hair thinning can occur for a number of other reasons as well. It is a common phenomenon among sows that are repeatedly bred, or in weak, newly weaned juvenile guinea pigs. Certain fungal diseases and external parasite infestations also present hair loss problems.

Heat stress or Heat stroke
Guinea pigs are very susceptible to heat stroke, particularly those that are overweight and/or heavily furred. Environmental temperatures above 85 degrees (29° C), high humidity (above 70%), inadequate shade and ventilation, overcrowding, and other stresses are additional predisposing problems.
Signs of heat stroke include panting, slobbering, weakness, reluctance to move, convulsions and, ultimately, death. This is a treatable condition if recognized early. Heat stressed guinea pigs should be moved to a cool area, and can be misted with cool water, although veterinary assistance should be sought immediately. Prevention of heat stroke involves providing adequate shade and proper ventilation wherever he or she is housed. Review our section on keeping your cavy cool.

Pneumonia is one of the most common bacterial diseases of the pet guinea pig. Respiratory infections are caused by a number of viral and bacterial agents including streptococcal pneumoniae, Bordetella bronchiseptica, and a gram-positive diplococcus. Many of the disease causing organisms inhabit the respiratory tracts of clinically normal guinea pigs. Conditions of stress, inadequate diet and improper husbandry will often predispose a pet to an opportunistic infection with one or more of these agents.
Symptoms of pneumonia may include dyspnoea (difficulty breathing), discharge from the nose and eyes, lethargy, and lack of appetite. The disease progresses rapidly, and in some cases, sudden death will occur without any of these signs.
Occasionally, middle or inner ear infections accompany respiratory disease in guinea pigs. Additional symptoms in these cases include incoordination, torticollis (twisting of the neck), circling to one side, and rolling. Veterinary consultation should be immediately sought when a guinea pig exhibits any of the above symptoms. A bacterial culture with antibiotic sensitivity of the throat and/or nasal discharge will assist the veterinarian in the selection of an appropriate antibiotic. Aggressive antibiotic therapy in addition to supportive care of the patient may be necessary. Unfortunately, even though elimination of the symptoms is often possible with appropriate therapy, eradication of the causative bacteria is not.

Bacterial Enteritis (Intestinal Infections)
A number of bacteria are capable of causing infections of the gastrointestinal tract in guinea pigs. One of the most common bacteria that cause intestinal disease in guinea pigs is Salmonella spp. Other bacterial species that may cause diarrhoea and enteritis are Yersinia pseudotuberculosis, E. coli and Clostridium spp. These bacteria may be introduced through contaminated greens or vegetables or in contaminated water. Others may grow if your guinea pig is stressed or if he is on an inappropriate antibiotic therapy.
Common symptoms include diarrhoea, lethargy and weight loss. In other cases, however, sudden death may occur before expression of these signs.
Treatment from your veterinarian includes aggressive antibiotic and pro-biotic therapy and supportive care to treat this condition. A bacterial culture of the patient's stool with antibiotic sensitivity will greatly assist the veterinarian in choosing an appropriate antibiotic. Keeping your guinea pig on a diet high in fibre and low in sugars can help prevent as well as reduce the incidence of this condition.

Bacterial Pododermatitis
Inactivity, poor housing and obesity are the primary contributors to bacterial pododermatitis (infections of the footpads). This is a common condition of guinea pigs, which begins with reddening and thinning of the skin and ends with infection and ulceration of the footpads. Not unlike bed sores, with constant pressure on the pads of the feet from inappropriate cage flooring (wire, or soiled and damp floor), these pressure wounds can become infected, very painful and a vicious cycle ensues: the less the animal moves, the worse the wounds; the worse the wounds, the greater the pain and the less the animal moves.
Bacterial pododermatitis is a chronic condition that is very difficult to manage and eliminate and is therefore best prevented by proper caging, well balanced and complete diet and daily exercise out of the cage.
Treatment includes patience, along with regular cleansing of the wounds, applying antibiotics and bandaging. It is often necessary to treat with injectable antibiotics.

External Parasites
Lice and mites are the most common external parasites of guinea pigs. Neither species that infects guinea pigs is known to parasitize man.

Mites are microscopic, spider-like organisms that infest the top layers of the skin in affected animals.
Mite infestations are usually more severe than lice. There are three different mites that parasitize guinea pigs. Two live on the coat: Chirodiscoides cavia and Cheletiella parasitovorax. The fur mite (Cheyletiella parasitovorax) typically infects rabbits and causes mange: thinning fur and dry flaky skin typically behind the ears (which is why the mite is sometimes referred to as walking dandruff).
A third mite, Trixacarus cavie, causes serious infestations and lives in the outer layers of skin in pet guinea pigs. Symptoms of this sarcoptic mite are an intense itching and scratching with considerable hair loss. In some cases, they are present without the itch and scratching, but hair loss and crusting of the skin is present. In other cases, the infestation and irritation is so severe that the pet causes significant self-inflicted wounds and exhibits wild running and circling behaviour.
A veterinarian can differ between mite infestations by performing skin scrapings of affected areas and viewing them under the microscope. Successful treatment consists of two to three injections of a specific antiparasitic drug at approximately two-week intervals. Long-term anti-parasitic prevention is now also available (Revolution?)
During or while waiting for treatment, wood shavings that are used as bedding or litter should be replaced with paper towelling to make your pet more comfortable, and his entire environment must be cleaned to prevent re-infestation. Transmission of Trixacarus cavie mites can occur only through direct contact between infested and non-infested guinea pigs. Therefore, guinea pigs are not likely to harbour this parasite unless they are recent additions or had previous exposure to mite-infested guinea pigs.

Two types of biting lice can parasitize guinea pigs. Both irritate and abrade the skin's surface and feed off the bodily fluids that exude through the superficial wounds they create. You can identify lice as tiny, wingless, flattened insects that live within the hair coats of infected animals. Both adults and eggs are found attached to hair shafts of affected pets.
Lice infestations often go unnoticed. However, heavy infestations are usually accompanied with excessive itching, scratching and some hair loss. Scabbing on or around the ears may also be evident.
A veterinarian can confirm the diagnosis of lice infestation by an examination of the hair coat as well as microscopic examination of hairs from affected animals. Treatment is usually in the form of an insecticidal treatment, which is prescribed by the veterinarian.
As with mites, lice transmission occurs through direct contact with infested guinea pigs. Therefore, pet guinea pigs are not likely to have this parasite unless they had previous exposure to lice-infested guinea pigs.

Ringworm (Trichophyton mentagrophytes) is a common fungal infection that results in hair loss and dry itchy skin, often seen in round patches on your guinea pig. Patches may first appear on the face around the eyes, nose and ears. A guinea pig usually acquires ringworm infection from another guinea pig or from contaminated bedding.
Confirmation of the fungus is made via culturing the fur and skin where the lesions are present. Treatment with oral anti-fungal medications along with a thorough cleaning of the environment is necessary. If you have guinea pigs living together, they may all require treatment or to be separated from the affected pig during treatment. Ringworm is contagious to other pets and immune suppressed individuals; it is prudent to contact your veterinarian immediately when you observe symptoms on your cavy.

Antibiotic sensitivity
Guinea pigs are very sensitive to certain classes of antibiotics. For this reason, never attempt treatment of your pet guinea pig at home without prior consultation with a veterinarian. Many antibiotics, which are safe for other animals, have been shown to be lethal to guinea pigs, whether given orally or by injection. In addition, even some topical antibiotics can produce serious detrimental results.
A partial list of potentially harmful antibiotics includes:

  • Ampicillin
  • Penicillin
  • Bacitracin
  • Gentamicin
  • Erythromycin
  • Lincomycin
  • Clindamycin
  • Vancomycin
  • Some Tetracyclines
Even if an antibiotic is not on this list, it does not ensure that it is safe to use. When improperly administered, any antibiotic can produce detrimental and often lethal results. The reason for this is that guinea pigs have very delicate digestive systems, so any alteration can produce a cascade of events leading to serious illness or death.
The primary mechanism behind this often-lethal effect is a dramatic alteration of the normal microbial balance in the gastrointestinal tract. In addition to affecting the disease-causing bacteria in the body, they also interfere with the normal beneficial bacteria in the guinea pig's digestive system. Along with the disruption of the bacterial balance, these alterations can also produce harmful toxins in the guinea pig's body. Other antibiotics cause direct toxic effects to the guinea pig without initially disrupting the digestive system, proving to be rapidly fatal.
Whenever a veterinarian prescribes any antibiotic, always supplement your guinea pig with a pro-biotic. Your veterinarian may prescribe a product that replaces beneficial bacteria, such as "Benebac". If not, you can supplement your guinea pig's diet with about one-half teaspoon of plain yogurt given twice daily, administered in between anti-biotic treatments. This therapy should continue for several days past the end of the antibiotic therapy. Probiotics helps augment and replace the beneficial intestinal bacteria that are compromised by the antibiotic treatment.
The bottom line is never attempt treatment at home without first consulting with your veterinarian.