Petriage Clinical Insights

IMPORTANT: This article, which is provided for educational purposes only, is based on published veterinary data and decades of work with pets and pet parents. The information provided here is not designed to be comprehensive but to help you avoid the pitfalls of online misinformation and most importantly, to frame the conversation you should have with your veterinarian. Your veterinarian’s perspective may differ from what is expressed here. Always consult with your veterinarian.


Diarrhea is one of the most common medical issues pet parents have to deal with. While most of the time diarrhea is not a medical emergency, it can be a sign of a serious condition, and should always be evaluated promptly. Even a moderate case which is not caused by a serious underlying condition can cause significant harm if unchecked, due to dehydration and other complications. In this discussion, we’ll look at how to assess your pet, and give you some practical advice for managing this condition.


  • There are numerous causes for diarrhea. In general, they are first classified as chronic (recurring) or acute (short duration) cases.
  • Diarrhea can be caused by a great many different conditions. Don’t assume that diarrhea is due to something your pet ate, or is even a gastrointestinal problem at all.
  • When your pet has a bout of acute diarrhea, pay close attention to your pet's behavior, demeanor and especially appetite. This will help you assess the urgency of the issue, and to decide if you need to get your veterinary team involved.
  • If any of these signs are present, your pet’s diarrhea should be addressed more aggressively. Contact your veterinarian to find out when your pet should be seen. Do not delay making contact, hoping that your pet will improve. If you are unsure, it’s better to be safe than sorry.
    • Diarrhea that has lasted more than 24-48 hrs.
    • A high volume of diarrhea instead of a series of small bowel movements.
    • Obvious lethargy (low energy).
    • Significant reduction or loss of appetite.
    • Blood in the stool.
    • Black stool, often with a tar-like texture.
    • Vomiting is present in addition to diarrhea.
    • Your pet seems to be in pain, especially around the abdomen.
  • Chronic diarrhea is loosely defined as diarrhea that is persistent despite initial treatment, or is recurrent on a frequent basis. These cases can be very frustrating to deal with from both a diagnosis and management standpoint. Chronic diarrhea is a medical puzzle that your veterinarian will need to solve. A step-wise, logical, and rational approach to diagnosing and treating these cases must be developed. This can take time and resources, and you as the pet parent must prepare yourself for this process. Some of these puzzles are more or less straightforward to solve, but some will require multiple diagnostic tests and might even involve veterinary specialists.


  • Pay attention to a few things about your pet’s diarrhea. These observations will be very helpful to your veterinarian in planning a course of action.
    • Has there been a significant increase in the frequency of bowel movements?
    • Is there a small volume or a large volume of stool?
    • Is your pet straining to defecate?
    • Is there any evidence of blood in the stool?
    • Is there significant slimy mucus on the stool?
  • Take photos of your pet’s diarrhea and share them with your veterinarian.
  • No matter when was the last time a fecal test was done, save a fresh stool sample in case your veterinarian wants to run new tests.
  • Significant diarrhea in a puppy or kitten can be dangerous due to the risk of dehydration. Pets which are unvaccinated or not fully vaccinated may be at additional risk. Always contact your veterinarian for advice when a young pet has significant diarrhea, even if your pet seems fine otherwise. 
  • For acute cases of diarrhea, as long as there is no vomiting present, provide plenty of water. This is especially important with diarrhea that is very watery and high in volume. Adding water or low-sodium chicken broth to your pet's food can provide extra hydration. Your vet may also suggest an oral rehydration solution, which provides vital electrolytes.
  • Do not give any antidiarrheal drugs unless instructed by your vet. Discontinue anti-inflammatory and pain medicines until your pet no longer has diarrhea. Consult with your vet about the need to stop other oral medications.
  • For acute causes of diarrhea, as long as there is no vomiting present, feed your pet bland food until the diarrhea subsides.
    • Your vet can recommend prescription diets.
    • You may give your pet baby food, but avoid types containing onion or garlic.
    • You may make your own low-fat, low-fiber diet at home with these instructions.
  • For chronic cases of diarrhea it is recommended that you keep a log of of every episode plus weekly pet weights. Your veterinarian can use this information to develop a diagnostic plan and monitor treatment efficacy.