Diarrhea in Guinea Pigs

Red guinea pig on hay looking up.

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Diarrhea is a common issue for many different kinds of pets, and guinea pigs are no exception. Soft, unformed stool is not only difficult to clean but can indicate a serious problem in your cavy. Knowing what could be causing this diarrhea and how it is safely treated can help keep your guinea pig healthy and clean.

What is Diarrhea?

Diarrhea is defined as loose, unformed, or watery stool. It occurs multiple times a day and unlike formed guinea pig droppings, diarrhea is messy, smelly, and abnormal.

Symptoms of Diarrhea in Guinea Pigs

If your guinea pig is not acting normally or has had recurrent diarrhea for more than a day, take it to your veterinarian as soon as possible.


  • Loose, soft, or unformed fecal pellets
  • Messy rear end
  • Dirty bedding
  • Foul smell
  • Sunken eyes

Unformed Fecal Pellets

The most identifiable symptom of diarrhea in your guinea pig is the loose, soft, and unformed fecal pellets it will leave in its cage. Your pet's poop should not be wet or mushy. They should be a bit firm, smooth and uniform in shape (normal pellets will look almost like plump grains of rice), and darkish brown. If the shape of the pellet is not uniform in its shape and density, there is a problem.

Messy Rear End

If you aren't seeing normal, formed fecal pellets in your guinea pig's cage, you may instead find fecal matter built up on its hind end. Diarrhea doesn't easily drop off of a guinea pig as does normal poop and will instead stick to the fur and legs.

Dirty Bedding

Some soft, loose, or unformed fecal pellets will be noticeable in the cage, but guinea pigs with diarrhea often have extra dirty bedding. Normal fecal pellets do not soak into the bedding as watery diarrhea does.

Foul Smell

The messy rear end and dirty bedding will result in a foul smell in the cage. The diarrhea may have also stained the fur around your cavy's anal area which may also contribute to the smell.

Sunken Eyes

Finally, if diarrhea is not addressed, dehydration can easily occur resulting in the eyes appearing to be sunken into the head.

Causes of Diarrhea

Guinea pigs can develop diarrhea due to a variety of things. Some of the most common causes include:

  • Improper diet: Diarrhea can result in a guinea pig that does not have an appropriate diet. An imbalance of good bacteria in the gut, hypovitaminosis, excess water, and a lack of fiber can cause stools to be runny.
  • Bacterial or viral infection: Infections can disrupt a healthy gut and cause diarrhea in your guinea pig if they become a systemic problem. Respiratory issues, an overgrowth of bacteria in the gut, and even infected wounds that go without treatment may cause diarrhea.
  • Parasitic infection: While intestinal parasites are not common in guinea pigs, they can be infected with external parasites like mange and lice. These parasites can be annoying or even painful to your guinea pig and cause them to be stressed and develop diarrhea.
  • Stress: Any disease or infection can cause animals stress. But there are also environmental stressors that can cause diarrhea. New cage mates, other pets, children, or noises outside the cage, moving, temperature changes, and other things can cause your guinea pig's stools to be soft and not formed well.
  • Other diseases: Various cancers and other diseases can result in diarrhea depending on how it affects your guinea pig.

Diagnosing Diarrhea in Guinea Pigs

Clear clinical signs will let your veterinarian know your guinea pig has diarrhea. But the doctor will need to diagnose the cause. Your veterinarian may need to run some tests after performing a physical examination to determine the reason for the diarrhea if it is not obviously related to diet or environment.


In order to treat the diarrhea, you'll need to know the underlying reason for it. Diet may need to be corrected by adding in Vitamin C or more fiber, environmental stressors may need to be eliminated, and infections, parasites, and diseases may require various medications. Fluids may also need to be administered if your guinea pig is dehydrated because of the diarrhea.

Prognosis for Guinea Pigs With Diarrhea

A guinea pig that is promptly treated for diarrhea and its cause will likely go on to lead a normal life unless the condition is the symptom of a more fatal disease. Untimely treatment of the diarrhea may result in severe dehydration and death.

How to Prevent Diarrhea

There are ways to aid in the prevention of diarrhea in guinea pigs. Make it a habit to maintain these three parts of your cavy's life:

  • Diet: A guinea pig's diet should be high in fiber along with dark, leafy vegetables to maintain a healthy gut and help avoid diarrhea. An inappropriate diet is a common reason for diarrhea but also a very avoidable one.
  • Cage: Your guinea pig's cage should be kept away from drafts to help prevent them from getting sick. Locate the cage away from areas where cats, dogs, and other pets may cause them to feel threatened frequently. Cages should also be cleaned regularly to avoid a dirty environment that could cause an infection.
  • Quarantine: New guinea pigs should be quarantined for at least a week before being introduced to your older pigs. This can help prevent spreading parasites that can stress a guinea pig and result in diarrhea.