Things Your Vet Might Recommend for Your Pet’s Diarrhea

SFSBlog_diarrhea_madartichoke_together_FlickerCCDiarrhea becomes a fact of life for most of our pets at some point or another. If the diarrhea persists for more than a few days or is recurrent, it’s a good idea to check in with your veterinarian even if your dog or cat seems to be feeling just fine otherwise.

Beyond performing a thorough physical examination, there are a number of things your veterinarian may recommend. Below is the rationale behind these recommendations.

Diagnostic testing

Whenever possible, having a diagnosis in hand (ugh, given the topic, this sounds kinda gross) is the very best path for getting the problem resolved. A variety of diagnostic tests are readily available to determine the cause of your pet’s diarrhea. The usual starting point is a fecal exam to look for intestinal parasites. Next come blood and urine testing to rule out underlying issues such as hyperthyroidism (kitties), liver or kidney disease. Specialized blood testing looking for issues such as inadequate production of digestive enzymes, decreased levels of folate or cobalamin (both are B vitamins necessary for normal gut health), or hormonal imbalances that can cause diarrhea may be indicated. If results from these tests fail to provide a diagnosis, imaging , typically x-rays and/or abdominal ultrasound, is the usual next step. Lastly, your veterinarian may recommend getting an up close and personal look at the bowel and collection of biopsies by way of either surgery or endoscopy.

Empirical therapy

Empirical therapy refers to administration of treatment without knowledge of the underlying diagnosis. Such therapy will likely be recommended for your pet’s diarrhea should you and/or your veterinarian determine that the testing needed to establish a diagnosis isn’t feasible. Listed below are empirical treatments commonly recommended for dogs and cats with diarrhea.


Intestinal parasites are a common cause of diarrhea in dogs and cats. Depending on the life cycle of the worms, sometimes they and/or their eggs simply don’t show up on fecal screening. For this reason, your veterinarian may recommend empirical deworming with fenbendazole, a highly effective broad spectrum executioner of most intestinal parasites.

Food trial

Your veterinarian may recommend a novel protein diet to help rule out a food-responsive enteropathy, in essence, a food allergy that can cause diarrhea. Back in the day when I was just a pup, we would prescribe lamb for such food trials. Lamb has become such a common ingredient in commercially prepared foods, that, by the time they arrive at adulthood, most dogs have already been exposed to it. Nowadays, novel protein sources such as kangaroo, ostrich, rabbit, quail, alligator, and duck are commonly recommended. Some veterinarians prefer hydrolyzed protein diets in which the protein has been broken down into molecules that are so small they escape detection by the immune system, thus avoiding an allergic reaction.

When fat is not properly absorbed within the gut, diarrhea is a predictable outcome. For this reason, your veterinarian may recommend a diet with reduced fat content.

The addition of fiber to the diet can be of benefit for diarrhea. Canned pumpkin is a commonly recommended source of fiber- good luck getting your kitty to eat this!

Food trials are typically prescribed for a four to six week time period, although improvement is often observed within the first couple of weeks.


Just like us our pets have different types of “normal” bacteria that reside within their gastrointestinal tracts. When there is shifting of bacterial populations such that there is overpopulation of some and crowding out of others, a variety of gastrointestinal symptoms, including diarrhea, can develop. This condition is referred to as antibiotic responsive enteropathy (formerly known as small intestinal bacterial overgrowth or SIBO). Your veterinarian may recommend empirical treatment with a particular type of antibiotic along with a probiotic. The hope is that this combination will restore a healthier balance of bacterial flora within the gut.

I want to emphasize that bacterial infections within the bowel are as rare as the proverbial hen’s teeth. Any antibiotic you give for diarrhea should be aimed at treating antibiotic responsive enteropathy rather than infection. The exception to this is the diarrhea called granulomatous colitis, also known as histiocytic ulcerative colitis. Sometimes referred to as “Boxer colitis” because it occurs almost exclusively in Boxer dogs, this disease is caused by bacteria and responds dramatically to treatment with the antibiotic enrofloxacin (Baytril).

Other medications

Should the above steps fail to remedy your pet’s diarrhea, your veterinarian may prescribe any one of a number of empirical medications. They run the gamut from gut motility modifiers to intestinal coating agents to anti-inflammatory medications. Corticosteroids such as prednisone or prednisolone are recommended as empirical treatment for diarrhea. Steroids have the potential for lots of side effects, so thorough discussion with your veterinarian should precede their use.

Bear in mind that none of these empirical therapies are an ideal substitute for obtaining a diagnosis. If your pet’s diarrhea fails to resolve in response to any of the treatments recommended, revisiting the option of further diagnostic testing is warranted.

In general, veterinarians who specialize in internal medicine have the most expertise diagnosing and treating chronic or recurrent diarrhea. Your time and resources, and, most importantly, your pet may be best served by working with such a specialist.

Has your pet had chronic diarrhea? If so what was the cause? What treatment fixed or failed to fix the problem?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at,, local bookstores, and your favorite online book seller.

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8 Comments on “Things Your Vet Might Recommend for Your Pet’s Diarrhea

  1. Hi Helene,

    Thanks for your willingness to share your experience with Madison, heartbreaking as it is. I think people will learn from what you had to go through. My condolences to you on your loss.

    Best wishes,

    Dr. Nancy

  2. My Beloved Black Lab Madison, all of a sudden started having diarrhea but was fine otherwise. My vet is conservative and recommended feeding boiled chicken and rice for a few days and see if the diarrhea goes away or not. It didnt but was still wanting to eat her kibble. So we put her on Flaygl. It Still was not going away. We did blood work and urine analysis. It appeared normal. My vet thought it might be Inflamatory Bowel Disease so we tried meds for that but she was still having diarrhea. He then sent me to an internest for an ultrasound. She said her lymphonodes in her stomach area were enlarged and they would need to do a biopsy. My vet wanted to do a biopsy externally from her back leg lymphnode instead of doing the invasive putting a needle internally into the stomach area. He was leaving out of town and asked me to get hold of the Internist to verify that would give us the same result. Unfortunaty the Internest would not return my calls and kept telling the front desk to tell me to talk to my vet. This caused a Big delay in doing the biopsy (it ended up it was okay to do the external biopsy). The result was Devastating. She had Lymphoma. By this time it had
    been 7 weeks and Madison was not eating and diarrhea got worse. I rushed her to the oncologist. She told me there was a very small window and would only do one or two rounds of chemo to see if she would go into remission. It did not work. It was too late. Madison passed away a couple of weeks later when her body filled up with fluid. 2 things: Dont assume it is normal diarrhea and get blood work done sooner rather than later and then if normal, PLEASE FIND A CARING INTERNIST THAT WONT JUST TAKE YOUR $800 and then wont return a phone call!! GO IN PERSON IF YOU HAVE TO A DEMAND THEY SPEAK WITH YOU!!

  3. Hi Stephanie. I agree that inflammatory bowel disease (IBD) is typically not cured but rather managed over time. The diagnosis is made via bowel biopsies that demonstrate inflammatory changes. Thanks for sharing your experience and pumpkin tip!

    Dr. Nancy

  4. I have also read that dogs can have chronic inflammatory bowel disease (which I suppose is a general term that includes some of those conditions you described). In such a case, there may not be a “cure” but only improvement through management. Do you agree?

    Fenbendazole is a definite try for chronic diarrhea (worked for my corgi). There are plenty of “bad bugs” that can’t been seen, even on a fecal, and I think it’s prudent to first rule out the possibility of parasites in idiopathic cases.

    For maintenance, we use pumpkin, but it is dried (not canned). The product is called “Firm Up!” and it’s very easy to administer, especially in broth or wet foods. We also use Pro-Pectalin which is kaolin, pectin, and pro-biotics in a liver flavored tablet (also available in gel form). My dog seems to like both products very well.

    As a last resort we use loperamide (Imodium), but this is only to slow down severe cases. It does make my dog drowsy and just plain yucky feeling.

  5. My dog does not have chronic diarrhea, but she has twice developed mucusy diarrhea that I couldn’t get rid of with home treatment (bland diet, probiotics, Canine Enteric Support from Standard Process). Both times no parasites were found on a fecal exam, but my vet looked at a fecal smear under the microscope and saw large quantities of clostridium (a specific type of bacteria). While this is not proof that a bacterial overgrowth was the cause of her diarrhea (healthy dogs can also have clostridium in stools), the large numbers combined with her symptoms certainly pointed in that direction. Both times, she was treated with metronidazole (Flagyl) and a symptom reliever (combination of imodium and kaopectate without salicylates the first time; second time with Pro-Pectalin, a combination of kaolin, pectin and E. faecium, a particular probiotic strain), and her stools quickly returned to normal. In both cases, she had been abnormally stressed in the two to four weeks before the diarrhea started, which may have led to a clostridium overgrowth. I appreciated my vet checking the smear under the microscope, as it gave me a better idea of what might be going on, even though empirical treatment would have been the same even without knowing.

  6. Years ago, I had two dogs with chronic diarrhea. My regular vet did a bunch of tests and administered different medications for my male dog. Nothing worked. So he sent me to an internist. A change in food that included beet pulp fixed the problem immediately.

    Then a few years later, I had a female with chronic diarrhea. Same routine but nothing worked. Then a friend at work gave me probiotics for dogs. This was 30 years ago, and I had no idea what probiotics were. The probiotics worked for her like a dream.

    Luckily, both dogs didn’t have any underlying issues. But it was a problem.

  7. Hi Becky,

    Metronidazole is a commonly used medication for diarrhea. It works well against some parasites, is an anti-inflammatory medication in the bowel, and may be the drug selected to treat antibiotic responsive enteropathy (formerly known as small intestinal bacterial overgrowth).

    Best wishes to you and your Pug,

    Dr. Nancy

  8. What about metronidazole? My 5 year old pug has had intermittent diarrhea since she was 6 mos old and had pneumonia. My vet said all the antibiotics she had to have then messed up her system. (He did run several tests but found nothing i.e. parasites, allergies.) Metronidazole is the one thing that works for her now. She also was on Tylan powder for a while when the diarrhea was really bad and that helped.

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