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Causes of Sudden Death in Guinea Pigs

Melissa holds a bachelor's degree in biology and is a plant and animal enthusiast with multiple pets.


Why Guinea Pigs Suddenly Die

The sudden and unexpected loss of a beloved pet can be a very upsetting time. Many rodents, including guinea pigs, can pass away without apparent warning, even when everything seemed fine right before. This is, unfortunately, a somewhat common occurrence. Distraught pet owners often blame themselves or question their care of the animal, but the fact remains that sometimes it is impossible to know what happened for sure.

Guinea pigs are very popular pets, yet this does not mean they are not somewhat fragile. Guinea pigs have basic needs, but small deviations in their care requirements can have potentially lethal consequences. Poor genetics and unknown causes (called idiopathic) can also be to blame.

The only way to truly understand the condition of your pet is to have a necropsy performed. This procedure is important, particularly if you have another guinea pig (they are recommended to be housed with at least one other companion), to understand if the death was preventable so improvements can be made for the surviving cage mate. It will also contribute to our understanding of why guinea pigs sometimes pass suddenly.

Warning Signs to Look For

Sometimes it seems like pets can die for ‘no reason,’ but often there are symptoms that are simply not noticed in time. Small animals are adept at concealing their sickness until they are gravely ill; unfortunately, sometimes they do so until the point that they are on the verge of death. This is why it is imperative to take any subtle changes to your pig’s behavior very seriously, and a vet appointment should be arranged. Weighing your pet weekly is an excellent way to catch problems before they become critical.

Any of the following symptoms warrant immediate action. You'll want to arrange a vet appointment (with a vet experienced with rodents whenever possible) ASAP and consult a credible guinea pig website while you wait for your appointment (Guinea Lynx is excellent) [1][7][8][13][16][17].

  • Changes to the consistency of the droppings (soft, smaller than normal, etc.)
  • Diarrhea
  • Lethargy
  • Anorexia
  • Sleeping at unusual times
  • Weight loss
  • Blood in the urine
  • Straining to urinate
  • Trouble breathing
  • Discharge from the eyes or nose

Disease Symptoms That Indirectly Cause Sudden Death

It is incredibly important to remember that the side effects of certain diseases are often more deadly than the disease itself. The following symptoms or associated complications in guinea pigs are common causes of sudden mortality in guinea pigs.


Stress is a general term that can be mild to severe, and it can have numerous causes. All animals go through stressful events, but sometimes for guinea pigs, chronic stressors can be so intense that they can affect the animal's gastrointestinal tract [12]. Stress that is the result of medical problems and associated pain can cause the guinea pig to stop eating, which in effect can upset the balance of the GI. This can lead to stasis which makes poor appetite even worse. It is also known that stress can directly decrease gut motility by increasing the output of epinephrine that inhibits peristalsis [12][8][17].

Sources of possible guinea pig stress can include:

  • social stress (animal housed alone, incompatible cage mate, overcrowding),
  • recent stressful events such as moving the pig to a different cage, house, etc.,
  • changing the diet,
  • veterinary care, and many others.

Even if your pet has been subjected to these conditions, that doesn't necessarily mean that this was definitely the cause. Sometimes it can be impossible to know for sure.


While diarrhea is a common occurrence in humans and dogs without significant consequence, it can be life threatening in guinea pigs and requires immediate medical attention. Diarrhea can be caused by disease, improper diet (which upsets the GI tract and results in the growth of pathogens), viral, bacterial, and parasitic infection. Without treatment, dehydration will result, and eventually, a guinea pig can die from gastrointestinal related complications [7][11].


Anorexia may be the most significant cause of medical problems in guinea pigs. Guinea pigs are animals that must constantly eat high fiber foods such as hay to keep the gastrointestinal tract running properly. There are many problems that can cause a guinea pig to stop eating: stress, disease, poor nutrition, and sometimes a mix of all of those. Also occurring are anorexic guinea pigs where the cause is completely unknown, which has been shown in some studies, along with idiopathic apathy, to be the most common medical problems guinea pigs face [13].

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Gut Stasis (Ileus)

A common theme of this article is unrelated diseases, infections, and conditions resulting in harm towards the gut, which in effect can cause major problems for guinea pigs. As hind gut fermenters, guinea pigs must have access to hay and water at all times, which they digest in their cecum with the aid of a rich diversity of microorganisms that play an essential role in gut motility.

Should this balance be disturbed, gastrointestinal hypomotility, or the slowing of the GI tract, can result. Changes to the pH and bacterial populations then result in the production of toxins [11][12][13. Complete cessation of this movement is GI stasis, or ileus. Due to a favorable environment for pathogens such as E. coli and Clostridium, bacterial dysbiosis occurs and can cause many of the life-threatening problems in this article [8][11][12]. The guinea pig will obviously experience severe discomfort and stop eating, which exacerbates the problem.

Causes of GI stasis include but are certainly not limited to:

  • Poor diet (too much pellets, lack of hay, cereal products, foods high in sugar)
  • Anything that causes the guinea pig not to eat or drink (sipper malfunction)
  • Dental disease
  • Pain
  • Environmental changes
  • Metabolic disease
  • Inappropriate antibiotic use
  • Toxin ingestion
  • Certain drugs

Dental Diseases/Malocclusion

Dental disease is a common root of many problems in guinea pigs, with studies showing that on average, these issues show up in pigs aged about three years [14]. Dental problems, most notably malocclusion, can cause pain and discomfort in guinea pigs, resulting in anorexia and resulting malnutrition and gastrointestinal dysfunction.

These conditions are highly treatable by qualified veterinarians, but unfortunately, sometimes the problem can go untreated if the owner doesn't notice their pet is eating less. Causes of dental disease include, most commonly, lack of roughage (hay) that aids to file down the guinea pig's ever-growing teeth, scurvy (vitamin C deficiency), stress, congenital defects, and age-related malfunction [8].

View of normal-looking guinea pig molars (patient was diagnosed with osteolytic destruction of the rostral mandible)

View of normal-looking guinea pig molars (patient was diagnosed with osteolytic destruction of the rostral mandible)


In captivity, guinea pigs can suffer from many ailments that are a result bacterial, viral, fungal, and parasitic infections. Pneumonia is one of the most common infections that guinea pigs can get, followed by various gastrointestinal infections [1][8]. Some of the most known gastrointestinal problems in guinea pigs include antibiotic-associated enterotoxemia, bacterial enteritis, and diseases caused by parasites [8][13].

There are many ways that guinea pigs can become infected by opportunistic organisms, although poor husbandry, antibiotic use, and stress are common reasons [1][5][6][8][11]. Some common infections that can cause sudden death include:

  • Pneumonia/Upper Respiratory Infection (URI). Respiratory disease is often reported in guinea pigs and is known to occur in immunocompromised animals, mostly affecting the young and old. Bordetella bronchiseptica and Streptococcus pneumoniae are the most common pathogens associated with these diseases [8]. Respiratory illness can be contagious and carried by asymptomatic carriers [13][16].
  • Bacterial Enteritis. Gram-negative bacteria can wreak havoc in a guinea pig's predominately gram-positive gut flora if they are immunocompromised (from stress) or with antibiotic use. Such organisms include: E.coli, Salmonella spp, Clostridium piliforme, Campylobacter spp., and Pseudomonas aeruginosa.

Urethral Obstruction and Other Urinary Problems

Urolithiasis, or calculi stones of the bladder, are most prevalent in three-year-old guinea pigs on average [8][19]. Uroliths can also occur in kidneys, ureters, and urethra.

Calciuria is the presence of calcium in the urine, which may not be related to urolithiasis. While some calcium deposits in the urine is normal in guinea pigs, excess calcium precipitate or decreased water output can result in the thickening of the urine that can lead to cystitis in the bladder[4][8][19].

Female guinea pigs may be more prone to infection of the urinary system with gastrointestinal bacteria because the anus and urethral opening are closer together. Females are also more prone to urolithiasis, but males are more prone to developing life-threatening blockages resulting from this condition.

Poor nutrition (too high in calcium), genetic defects, decreased water intake, inactivity, and obesity are possible predisposing factors to urolithiasis [4][19]. Urine retention can lead to the formation of stones caused by 'urine sludging,' abscesses, tumors, and adhesions. These conditions can cause pain, which can lead to anorexia in addition to bacterial proliferation, which can cause sudden death when untreated.

Kidney failure certainly has a high associated mortality rate but usually occurs in older animals. Urinary tract infections (URI) can potentially be fatal if left untreated and chronic interstitial nephritis (CIN) is another urinary disease guinea pigs can get.

Malnutrition and Vitamin C Deficiency

Vitamin deficiency, notably not enough vitamin C, is a somewhat common problem in pet guinea pigs. Guinea pigs require a dietary source of vitamin C (which has important interactions with vitamin E and aids guinea pig's absorption of vitamin D[3][9][10]) since they cannot make their own, therefore it must be supplemented in the form of powders, fortified tablets, or vegetables high in the nutrient. High-quality guinea pig feed contains stabilized vitamin C, but unfortunately this nutrient is depleted when exposed to heat, light, and dampness; generally about half of the vitamin C content is lost in typical conditions within 90 days[8].

Guinea pigs deficient in vitamin C can exhibit many symptoms, and some, such as diarrhea and dental problems (causing the animal to eat less), can be life threatening. Poor nutrition can exacerbate other issues a guinea pig can suffer from and hamper recovery, such as infections.

The damaging effect of inadequate nutrition is more prominent in growing guinea pigs due to their rapid growth rate and limited nutritional stores, which make them more prone to nutritional deficiencies [15].


Of course, cancers can cause sudden and unexpected death in guinea pigs. Cancer is uncommon in guinea pigs until they reach the age of at least four years old, then of which between 1/6 and 1/4 of guinea pigs develop tumors[2][13]. Tumors in guinea pigs are sometimes treatable, but this depends on the type of the tumor and its location.

Guinea pigs may develop internal problems that may not be apparent to the owner until the often incurable problem develops severe symptoms towards the end of the animal's life. The most common cancer that guinea pigs develop is lymphosarcoma, a cancer of the lymphatic tissues. Cancers of the blood, such as leukemia, have a poor prognosis and are often fatal [2].


GI stasis can lead to excessive gas production which can cause the stomach and intestines to fill with gas. This gas, produced in small amounts during the healthy fermentation process, is normally removed by the movements of the gut, but in an animal with reduced or stalled GI movements, it can cause painful distention of the animal's stomach [11][12]. Sudden death can occur simply because the condition is painful and the guinea pig can go into shock, or other reasons.

Antibiotic Toxicity

Guinea pigs are extremely sensitive to antibiotic treatment, of which improper use (wrong dosage, wrong type) can lead to fatal enterotoxemia[5][8]. Some antibiotics should not be used with guinea pigs, and this is why it is very important to take sick guinea pigs to a vet that is familiar with them (preferably a board-certified 'exotic animal' vet) whenever possible. When suffering from antibiotic-related disease, the medication should be stopped immediately and the guinea pig should be given fluid therapy, syringe fed a high fiber food, and other supportive care.

Heart Attack and Stroke

Many guinea pig owners have reported sudden mysterious deaths of their guinea pigs that did not appear to be due to any of the conditions listed here (often without the aid of a necropsy). These anecdotal incidents are often said to potentially be caused by heart conditions such as heart attacks, heart defects, or the heart inexplicably 'stopping.' Some owners also suspect their guinea pigs died of a stroke, which is the interruption of blood flow to the brain which deprives it of oxygen, caused by many factors. While guinea pigs can live up to eight years or even more, genetics may be a factor that can cause some individuals to pass away earlier than expected.



  1. Axelson, Rick. Guinea Pigs- Problems.
  2. Cancers and Tumors in Guinea Pigs. PetMD
  3. Benevenga, N. J., et al. "Nutrient requirements of laboratory animals." Nutrient Requirements of the Gerbil (1995): 140-143.
  4. Johnson-Delaney, Cathy A. "Disease of the urinary system of commonly kept rodents: diagnosis and treatment." Seminars in avian and exotic pet medicine. Vol. 7. No. 2. WB Saunders, 1998.
  5. Ceran, Canan, et al. "Do antibiotics contribute to postoperative ileus? Contractile responses of ileum smooth muscle in Guinea pigs to long‐term parenteral ceftriaxone and ampicillin." ANZ journal of surgery 76.11 (2006): 1023-1026.
  6. Choi, Hong Kyu, et al. "Inflammatory responses in the muscle coat of stomach and small bowel in the postoperative ileus model of guinea pig." Yonsei medical journal 54.6 (2013): 1336-1341.
  7. Diarrhea in Guinea Pigs
  8. Donnelly, Thomas. “Guinea Pigs.” Merk Manual Veterinary Manual, The Kenneth S Warren Institute, 2019.
  9. Fish, E. Wilfred, and Leslie J. Harris. "XI.The effects of vitamins C deficiency on tooth structure in guinea-pigs." Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character 223.494-508 (1934): 489-510.
  10. Hill, Kristina E., et al. "Combined deficiency of vitamins E and C causes paralysis and death in guinea pigs." The American journal of clinical nutrition 77.6 (2003): 1484-1488.
  11. DeCubellis, Julie, and Jennifer Graham. "Gastrointestinal disease in guinea pigs and rabbits." Veterinary Clinics: Exotic Animal Practice 16.2 (2013): 421-435.
  12. Johnson, Dan. “How I treat gastrointestinal stasis in small herbivores (Proceedings)” dvm360, CVC IN KANSAS CITY PROCEEDINGS, , URL.
  13. Knegt, S. de. Welfare assessment in young pet rabbits and guinea pigs in the Netherlands. MS thesis. 2013.
  14. Legendre, Loïc FJ. "Malocclusions in guinea pigs, chinchillas and rabbits." The Canadian Veterinary Journal 43.5 (2002): 385.
  15. Lykkesfeldt, Jens, et al. "Vitamin C deficiency in weanling guinea pigs: differential expression of oxidative stress and DNA repair in liver and brain." British journal of nutrition 98.6 (2007): 1116-1119.
  16. Minarikova, A., et al. "Diseases in pet guinea pigs: a retrospective study in 1000 animals." Veterinary Record 177.8 (2015): 200-200.
  17. Wellness Tips and Signs of Illness: Guinea Pigs
  18. Whittington, Julia. "Urinary diseases of exotic pets (Proceedings)." DVM 360.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.


Moon light on June 23, 2020:

So nice I’ve got two guinea pigs one is a baby and one is a big fat one

Taylor P on May 07, 2020:

my two year old guinea pig died a couple hours ago and im still heartbroken

Carolyn D-G on March 22, 2020:

What is the longest time that took a guinea pig to potty train?

Steve on December 20, 2019:

My daughters 3 1/2 year old male guinea pig (Cookie) died 6 days ago. His death seemed painful but am still not sure what he died from. He seemed to be having seizures the last couple of hours before he died. He seemed to be good one day and in horrible shape the next. He was a Very loved piggy and such a good boy. He will be missed.

Sara on October 23, 2019:

Well my guinea pig head sisters and they all died the day before yesterday and today

Melissa A Smith (author) from New York on October 13, 2019:

Beka: We won't know without knowing what happened to the other, but eventually you'll probably want to get another companion for her. I think things should be fine as long as appetite, defecation, and energy level are normal, but you can take her in for a wellness exam to be absolutely sure.

Beka on October 10, 2019:

Our guinea pig Lessie died this morning. He does have a mate in the same cage as he was. Should we be worried whatever made Lessie die will harm the other? There has been no change in environment or food. This has come as a complete shock to our family. He was so loved.

Katlee on October 08, 2019:

My brothers guinea pig died 2 days ago

Alexander James Guckenberger from Maryland, United States of America on March 22, 2019:

These guys are adorable.

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