Health Problems in Guinea Pigs

By Gregory Rich, DVM; Kyra Berg, DVM, DACZM; Laurie Hess, DVM; Rick Axelson, DVM

Guinea pigs can be hardy and easy to care for when provided an appropriate environment for their unique needs. Like all animals, guinea pigs are susceptible to certain problems and diseases. The following is a brief description of some of the more common problems of guinea pigs, which include respiratory infections, gastrointestinal diseases, scurvy (vitamin C deficiency), tumors, abscesses due to infection, urinary problems, fungal skin infections and infestations by lice and mites.

Respiratory Infections

Pneumonia is one of the most significant diseases of pet guinea pigs and can be caused by several bacteria, including Bordetella, Staphylococcus, and Streptococcus. Guinea pigs can naturally harbor these bacteria and may be asymptomatic (apparently healthy) carriers. These bacteria tend to be 'opportunistic,' meaning they infect susceptible animals, multiply, and cause disease if the opportunity arises.

"Pneumonia is one of the most significant diseases of pet guinea pigs."

Inner Ear Infections

Guinea pigs are very prone to inner ear infections. Symptoms often present as a head tilt, but may also show up as just weight loss and poor eating habits. Diagnosis is made by radiographs of the skull and noting fluid in the inner ear (tympanic bulla). Treatment usually involves several weeks of antibiotic and anti-inflammatory therapy. In severe cases, a delicate and specialized surgery may be performed to puncture the eardrum and suction out the fluid/pus.

Stressors such as overcrowding, pregnancy, and the presence of other illness, increases the chance that infection will develop. Young animals are most often affected. The bacteria are spread by direct contact, aerosolized (airborne) particles, and on contaminated hands or other objects. Infected guinea pigs may stop eating, have discharge from the eyes or nose, sneeze, or have trouble breathing. Cultures of the eye and nasal discharge can be taken to identify the causative organism so that the appropriate antibiotics can be prescribed. Some guinea pigs may need to be hospitalized for additional supportive care, especially if they are having trouble breathing. A guinea pig who is open-mouth breathing warrants immediate evaluation by a veterinarian.

"A guinea pig who is open-mouth breathing warrants
immediate evaluation by a veterinarian."

Gastrointestinal Diseases

Like rabbits, guinea pigs have a sensitive gastrointestinal tract. They have a very specific natural population of “good” gastrointestinal bacteria (flora) critical to normal bowel function. If this normal bacterial flora becomes altered or unbalanced, “bad” bacteria can overgrow, produce painful gas, and slow down digestion and food passage through the gastrointestinal tract. This can damage the intestinal tissues, release toxins, cause diarrhea, and if left untreated, death. This condition is referred to as gastrointestinal stasis (or GI stasis). In addition to bacterial infections, some intestinal parasites, like Cryptosporidium, Giardia and coccidia, can cause diarrhea.

Other clinical signs that may occur with GI stasis include anorexia (not eating), depression, dehydration, weight loss, diarrhea, and a low body temperature. Guinea pigs with these signs need immediate veterinary attention and supportive care. A low body temperature in guinea pigs has been associated with decreased survival, so a sick guinea pig always warrants rapid veterinary evaluation.

Dental disease is common in guinea pigs and may be caused by low-quality diets, vitamin C deficiency, infection, and trauma. Diagnosis can be achieved with a thorough oral examination. Complete assessment of the extent of dental disease is best performed through a CT scan of the skull, although radiographs (x-rays) can be performed if a CT scan is not available or possible. While generally not considered curable, dental disease can be managed through routine dental adjustments under anesthesia performed by a skilled veterinarian as well as at-home care.

"Certain antibiotics should never be used in guinea pigs, as they upset their normal gastrointestinal bacterial flora..."

Certain antibiotics should never be used in guinea pigs, as they upset their normal gastrointestinal bacterial flora, called dysbiosis, and can rapidly lead to fatal diarrhea. Antibiotics purchased over-the-counter in a pet store should never be given to guinea pigs for this reason. Antibiotics should be used in guinea pigs only under the direction of a veterinarian familiar with guinea pigs.

Scurvy (Vitamin C deficiency)

Guinea pigs and primates cannot produce their own vitamin C; therefore, they must consume vitamin C in their diets. Vitamin C is vital for the normal development and maintenance of skin, joints, and mucosal surfaces, such as the gums. It is also important in wound healing and normal immune system function. Lack of vitamin C can make guinea pigs more prone to the development of other diseases, including infections. Some clinical signs of vitamin C deficiency in guinea pigs can include a rough hair coat, reluctance to walk, swollen feet or joints, and bleeding and/or ulcers on the gums or skin.

"Guinea pigs need 10-50 mg of vitamin C per day, depending on the condition of the animal "

Guinea pigs need 10-50 mg of vitamin C per day, depending on the condition of the animal (eg: young, old, stressed, healthy, pregnant). Vitamin C should not be added to the water because it can change the taste of the water, which may lead to decreased water consumption. Furthermore, vitamin C degrades rapidly in water, so it is not a long-term feasible supplementation for guinea pigs. Commercial vitamin C tablets designed for small mammals are available at major pet stores nationwide, and should be provided in addition to the vegetables mentioned above. A liquid vitamin C supplement can also be provided by mouth if your guinea pig will not eat the tablets.

Commercially available pellets made for guinea pigs contain vitamin C; however, this vitamin is relatively unstable and breaks down very rapidly. Therefore, the pellets should be used or completely replaced within 90 days of the date of manufacture. The following vegetables are good sources of Vitamin C for Guinea Pigs; bell peppers, broccoli florets, cauliflower florets, and parsley. Consult your veterinarian as to the best way to supplement your guinea pigs with vitamin C.


Guinea pigs get various tumors; skin and mammary (breast) tumors are the most common. Trichoepithelioma, a benign tumor of abnormal hair follicles that grow under the skin, is very common in adult Guinea Pigs. Most skin tumors are benign, but most mammary tumors are malignant in both male and female guinea pigs. Any mass should be brought to the attention of your veterinarian. In many cases, surgical removal is curative.


Abscesses are infected swellings that contain an accumulation of pus and bacteria, and can affect lymph nodes, skin, muscles, teeth, bones, and internal organs. Since guinea pigs form thick pus that does not drain or get reabsorbed easily, most abscesses in these animals require surgical removal, followed by treatment with antibiotics chosen based on culture of the bacteria growing in the abscess. Some abscesses (like those involving the jaw and teeth) are more challenging to treat, as affected teeth and bone must be removed along with all the infected soft tissues. Abscesses secondary to dental disease tend to be more complex, have a decreased risk of complete cure, and can take a longer time to control if a cure is not possible.

Reproductive Disease

Sows give birth to 2-4 fully developed, relatively large, fully furred pups with open eyes and the ability to eat solid food (although they will still nurse). A baby guinea pig is called a pup or young, but not a piglet.

"A baby guinea pig is called a pup or young, but not a piglet."

The average gestation period for guinea pigs is 63 days. If gestation continues over 70 days, the guinea pig should be seen immediately by a veterinarian, with a high risk that the entire litter could be stillborn. Difficulty in giving birth is known as dystocia, and is more likely to occur in females that have not had a litter before 8 months of age. After about 8 months of age, a female guinea pig's pelvic bones become more tightly fused, so passing naturally large pups can be more difficult.

When the mother has not received appropriate nutrition during her pregnancy, or when she has a large litter of these naturally large pups, she may be at risk for developing a life-threatening condition called pregnancy toxemia. This is a metabolic disorder causing the pregnant female to have low blood calcium and high blood pressure. It manifests as loss of appetite in the early stages, deteriorating to muscle twitching, seizures, and coma. Prompt veterinary attention can save affected animals, but the likelihood of developing the problem can be reduced by providing the pregnant guinea pig with plenty of water, high-calcium greens, and access to alfalfa hay during pregnancy. Ideally, all pregnant guinea pigs should be checked by a veterinarian to try to prevent pregnancy-related problems. During nursing times, both the mother and pups should have access to alfalfa hay.

Ovarian cysts are common in female guinea pigs, with older females more frequently affected. Cysts can either be non-functional or functional. Non-functional cysts may cause discomfort if they are large in size and push on other abdominal organs. Functional cysts are hormone-producing and can lead to hair loss, aggression and mounting behaviors, and thickened nipples. Because of the possibility of concurrent uterine disease, spaying is the recommended treatment option for functional and uncomfortable non-functional cystic ovaries.

Urinary Problems

Urine drains from the kidneys to the bladder by way of tubules known as ureters. Then, urine travels from the urinary bladder through the urethra and out of the penis in males or urinary papilla in females. Guinea pigs are very prone to the development of urinary calculi (stones or uroliths). Stones may be caused by inflammation, infection, and possibly diet. These stones most often form in the bladder but may also form in the kidneys or ureters. Stones may become lodged in the ureter or the urethra as they are being passed, causing a painful and possibly life-threatening obstruction. Male guinea pigs are especially at high risk for life-threatening obstruction of stones in their urethra. Immediate veterinary attention is required to diagnose and treat urinary calculi. Recurrence of stones is common and no definitive preventive treatment is available at this time. Other urinary diseases include cystitis (inflammation) which can occur with stones, and urinary tract infections (UTIs).

Clinical signs of urinary problems include not eating, blood in the urine, straining to urinate or vocalizing during urination, hunched posture, urine staining, or small frequent urination. Complete inability to urinate may be indicative of an obstruction. Any guinea pig with signs of a urinary tract problem should be seen by a veterinarian right away.

"Guinea pigs are very prone to the development of urinary calculi (stones or uroliths)."

Veterinarians diagnose urinary problems with a thorough history and physical examination, including abdominal palpation (examination by feel), blood tests, urinalysis, and X-rays. Sick guinea pigs may require hospitalization and supportive care, including intravenous fluids and syringe feeding, as well as surgery to remove the stones. Regular, annual veterinary check-ups can help detect problems, such as urinary tract stones, in guinea pigs before they develop into life-threatening emergencies.

Skin Diseases

Pododermatitis, or bumblefoot, describes pressure sores that develop on the bottoms of the feet. This is a common and very uncomfortable disease in guinea pigs. It occurs most often in guinea pigs who are overweight, arthritic, and/or housed on wire-bottomed or dirty cages that abrade the feet. The sores make guinea pigs susceptible to chronic, deep bacterial infections that cause lameness and pain. Treatment is challenging, and requires routine veterinary care in conjunction with diligent at-home care. Some treatment options include environmental at-home adjustments, medications, foot baths, foot bandages, and surgery. Sharing your current at-home set-up for your guinea pigs with your veterinarian at their annual examinations reduces the risk of this generally preventable skin condition.

Adult and especially young or immunocompromised guinea pigs are prone to dermatophytosis (ringworm), which is a fungal infection of the skin. Certain animals may be carriers without showing any signs of illness. They can spread the disease to susceptible animals or develop disease themselves if stressed by overcrowding, poor nutrition, other diseases, or other environmental stressors. The skin affected by dermatophytes can be very itchy, resulting in hair loss and crusts (scabs). Ringworm lesions are found most commonly around the face, head, and ears, but can spread to the back and legs. After diagnosis by your veterinarian, affected guinea pigs are treated topically and/or orally with anti-fungal medications. Dermatophytosis can spread from guinea pigs to humans, so make sure to wear gloves and wash your hands when treating your guinea pigs.

"Ringworm can spread from guinea pigs to humans, so make sure to wear gloves and wash your hands when treating your guinea pigs."

Guinea pigs can get fleas and lice. Fleas are usually diagnosed by finding the adults or their feces on the skin or in the fur. Lice are often diagnosed microscopically by observing either the adult lice or eggs (nits) in a sample of hair and skin debris. Lice eggs are laid on the hair shafts, often around the face, behind the ears, or over the shoulders. Mite infestations in guinea pigs can cause such intense itching that they scratch themselves so intensely that they appear to be having a seizure. With a mite infestation, the skin is crusty and raw from scratching with hair loss and sometimes secondary bacterial infections. These parasites are best treated with anti-parasitic medications prescribed by your veterinarian. Secondary bacterial skin infections should be treated with antibiotics.

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