Health Problems in Guinea Pigs

By Laurie Hess, DVM; Rick Axelson, DVM

Guinea pigs are easy to care for and, if handled frequently and gently, make great family pets. They are generally hardy, healthy animals but 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, diarrhea, scurvy (vitamin C deficiency), tumors, abscesses due to infection, urinary problems, and infestations by lice, mites, or fungus.

Respiratory Infections

Pneumonia is one of the most significant diseases of pet guinea pigs and can be caused by several bacteria, including Bordetella 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."

Stress, such as overcrowding, pregnancy, and the presence of other illness, increases the chance that infection will develop, and 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 be off food, have discharge from the eyes or nose, sneeze, or have trouble breathing. Cultures of the ocular (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.


Guinea pigs have a sensitive gastrointestinal tract (as do rabbits). 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’ (often gas-producing) bacteria can overgrow, produce painful gas, slow down digestion and food passage through the intestinal tract, damage the intestinal tissues, release toxins, cause severe diarrhea, and in severe cases, death. This condition is referred to as gastrointestinal (or GI) stasis. In addition to bacterial infections, some intestinal parasites, like Cryptosporidium and coccidia, can cause diarrhea.

Other clinical signs that may occur with diarrhea include anorexia (not eating), depression, dehydration, weight loss, a low body temperature. Guinea pigs with these signs need immediate veterinary attention and supportive care.

Certain antibiotics should never be used in guinea pigs, as they upset their normal gastrointestinal bacterial flora and often lead to diarrhea. Antibiotics should be used in guinea pigs only under the direction of a veterinarian familiar with guinea pigs. Antibiotics purchased over-the-counter in a pet store should never be given to guinea pigs, since they are often inappropriate.

Scurvy (Vitamin C deficiency)

Guinea pigs and primates cannot manufacture their own vitamin C; therefore, they must take in vitamin C in their diets. The majority of other animals can produce their own vitamin C through their intestinal bacterial flora, but guinea pigs and primates are unable to do this. Vitamin C is vital to the normal development and maintenance of skin, joints, and mucosal surfaces, such as the gums. It is also important in the healing of wounds. As well as predisposing the guinea pig to skin problems, a lack of vitamin C makes the body more prone to the development of other diseases, including infections. A guinea pig that has a rough hair coat, is off his food, has diarrhea, is reluctant to walk, seems painful, has swollen feet or joints, or has hemorrhages and ulcers on its gums or skin, is likely to be deficient in vitamin C.

"Guinea pigs and primates cannot manufacture their own vitamin C; therefore, they must take in vitamin C in their diets."

Guinea pigs need 10-50 mg of vitamin C per day, depending on the condition of the animal (young, old, stressed, healthy, pregnant). Commercially available pellets made for guinea pigs contain vitamin C; however, this vitamin is relatively unstable and breaks down or oxidizes very fast. Therefore, the pellets should be used up or must be replaced within 90 days of the date of manufacture. If your guinea pig develops signs of vitamin C deficiency, it is important to take him to see your veterinarian as soon as possible. To prevent vitamin C deficiency, guinea pigs should receive a vitamin C supplement, either as a tablet or liquid given by mouth, rather than in the drinking water, as the vitamin also breaks down rapidly in water and loses its potency. Consult your veterinarian as to the best way to supplement your guinea pig with vitamin C.


Guinea pigs get various tumors; skin and mammary (breast) tumors are particularly common. They can be benign or malignant (cancer). Any mass should be brought to the attention of your veterinarian. In many cases, surgical removal is curative.


Abscesses (infected swelling containing an accumulation of pus and bacteria) can affect lymph nodes, skin, muscles, teeth, bones, and internal organs. Since guinea pigs (and other rodents and rabbits) form thick pus that does not drain or get reabsorbed easily, most abscesses in these animals require surgical removal (debridement), 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.

Urinary Problems

Guinea pigs are very prone to development of urinary calculi (stones or uroliths). These stones most often form in the bladder but may also form in the kidneys or ureters (tubes that drain the kidneys into the bladder). Stones may become lodged in the ureter or the urethra (the tube carrying urine from the bladder to the outside), causing a life-threatening obstruction.

Although uncommon, cystitis (bladder infection) occurs more often in female guinea pigs than males, and often stones develop in association with infection. Signs of urinary problems include anorexia (not eating), blood in the urine, straining to urinate, a hunched posture (with straining), and small, frequent urinations; if an obstruction occurs, the guinea pig will be unable to produce urine. Any guinea pig with signs of a urinary tract problem should be seen by a veterinarian right away.

"Guinea pigs are very prone to 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.

Parasites and Skin Problems

Guinea pigs (especially young ones) are prone to ringworm, which is an infection of the skin with a fungus, not with a worm. Certain animals may be ringworm 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, the presence of other diseases, or other environmental stresses. The skin affected by ringworm can be itchy, lose hair, and develop crusty 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.

"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."

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 adults 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 seizures can result. With a mite infestation, the skin is crusty and raw from scratching, there is usually hair loss and secondary bacterial infection may result. These parasites are best treated with anti-parasitic medications prescribed by your veterinarian. Secondary bacterial skin infections should be treated with antibiotics.

Other Problems

Barbering is a problem, usually associated with boredom, in which the guinea pig chews or barbers its own hair or the hair of its cage-mate, so that the barbered pig looks like it has been given a brush cut. Treatment involves providing the guinea pig with more stimulation, redirecting its attention to other chewing activities by offering more hay or chew toys, and separating guinea pigs if they are barbering each other.

Pododermatitis, or bumblefoot, in which sores develop on the bottom of the feet from pressure, is common in guinea pigs. It occurs most often in overweight animals housed on wire-bottomed or dirty cages that abrade the feet, making them susceptible to chronic, deep bacterial infection that causes lameness and pain. Treatment is challenging, but with appropriate veterinary care, including surgery, foot bandages, and antibiotics, the problem can be alleviated.