Diarrhea in Guinea Pigs

Red guinea pig on hay looking up.

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Diarrhea is a common issue in 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 in Guinea Pigs?

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.

Signs of Diarrhea in Guinea Pigs

Clinical Signs

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

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 like normal poop does and will instead stick to the fur and legs. This quickly creates a messy rear end in addition to a foul smell. Some soft, loose, or unformed fecal pellets may be noticed 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. Finally, if diarrhea is not addressed, dehydration can easily occur resulting in the eyes appearing to be sunken into the head.

Causes of Diarrhea in Guinea Pigs

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

  • Improper diet - If a guinea pig is not being offered and eating an appropriate diet, diarrhea can result. 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 - While any disease or infection can cause stress on a body, 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 disease - Various cancers and other diseases can result in diarrhea depending on how it affects your guinea pig.


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.

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.

How to Prevent Diarrhea in Guinea Pigs

Guinea pigs should eat diets high in fiber along with dark, leafy vegetables in order to maintain a healthy gut and help avoid diarrhea. Inappropriate diet is a common reason for diarrhea but also a very avoidable one.

Your guinea pig's cage should be kept away from drafts to help prevent them from getting sick along with avoiding areas where cats, dogs, and other pets that may cause them to feel threatened frequent. Cages should also be cleaned regularly to avoid a dirty environment that could cause an infection.

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.

Finally, 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.