Diarrhea is going to happen if you have a dog. And it usually occurs at the worst possible time, like when you’re all dressed up and ready to go out for your birthday dinner or renting an AIR BNB on vaca…

Those were two of my most memorable experiences of our dog having blow out diarrhea. The other was when my now husband called me from vet school to tell me our dog’s diarrhea “hit all four walls!” and wanted me to solve the problem through the phone. Diarrhea is bad news for everyone involved.

The good news is it’s not always serious. Here are some things you need to know about dog diarrhea, including how to tell if it’s serious enough for a vet visit.

The Most Common Causes of Diarrhea In Dogs

Dog looking at chickenDiarrhea is one of the most common presenting symptoms of enterocolitis. Enterocolitis is rapid onset of inflammation of the small and/or large intestines.

The number one cause of dog enterocolitis is called dietary indiscretion. This may happen due to a change in diet, your dog eating something he’s not used to, eating something spicy or fatty or eating a diet that he/she is allergic to.

Dogs eating only highly processed, dry kibble are more likely to develop diarrhea for a few reasons. One being that their gut is not used to variety, so any slight change in diet brings on symptoms. Another reason is that dry, processed kibble does not support a varied, healthy intestinal flora, leaving these dogs less able to deal with any changes in their gut.

Feeding a diverse, flexible whole food, meat-based diet is the best way to build a healthy gut in your dog.

Other common causes of dog diarrhea:

Garbage Gut
This can be something your dog got into while counter surfing or raiding the trash can. This also includes ingestion of plants, toxins, foreign objects, and table scraps. These can cause inflammation of the gut lining and result in diarrhea.

Viral Or Bacterial Infections
This can happen due to a weakened immune system. About 90% of your dog’s immune system is found in the gut. So if beneficial bacteria is low, problem bacteria or a virus can take over and cause problems.

One common viral disease in dogs that causes diarrhea, especially in puppies, is parvovirus. Other viral causes include coronavirus and distemper virus. If you have a puppy with diarrhea, it’s better to be safe and have your vet check him/her out.

A bacterial infection can develop from food poisoning caused by contaminated food or weakened immune system. It can also develop from a weakened immune system. Types of intestinal bacterial infections include Salmonella, Campylobacter, Clostridium and E.coli.

Puppies are usually more prone to get parasites, but it can happen to any dog. Parasites include worms like roundworms, hookworms, whipworms, and tapeworms. Protozoal infections such as giardia and coccidia can cause severe, chronic diarrhea.

Stress Colitis
This is a common cause of diarrhea, especially when your dog is boarded or is away from you for a prolonged period of time. Other changes such as moving, dramatic change in routine, hospitalization, travel, construction in the house, new baby, separation anxiety or additional of a household pet can all be potential causes for stress colitis.

Inflammatory Diseases
If your dog has colitis or inflammatory bowel disease (IBD), it can cause chronic diarrhea. This is an immune disorder that can be compounded by bacterial overgrowth and food allergies.

Other Disorders
Pancreatitis (inflammation of the pancreas), kidney disease, and liver disease can all cause bouts of diarrhea.

Intestinal neoplasia and exocrine pancreatic insufficiency are also causes of chronic diarrhea, and are often accompanied by weight loss.

Hypoadrenocorticism is a potential cause of acute or chronic diarrhea.

Drugs, especially antibiotics, can cause diarrhea. Antibiotics kill good bacteria along with the bad bacteria. Non-steroidal anti-inflammatories are a common cause of diarrhea and should be stopped immediately if gastrointestinal symptoms develop.

Do I need a vet visit?

Take your dog to your vet if he/she has 1 or 2 of these additional symptoms:

  • Loss of appetite or no interest in food
  • Not drinking, or he appears dehydrated (tacky gums, drawn appearance, decreased urination, decreased skin turgor)
  • Abdominal pain
  • Blood in the stool (dark, blackish or bright red blood)
  • Vomiting
  • Failure to urinate or reduced urination
  • Lethargy or weakness
Other reasons to make a vet visit:
  • A puppy, young or very small dog
  • Older or senior dogs
  • A dog with chronic health issues like diabetes, Cushing’s or cancer
Important testing for the following:
  • Acute diarrhea
  • Fecal with giardia test. Bring a sample of the stool to the vet for analysis.
  • Bloodwork to rule out a metabolic cause
  • Radiographs if vomiting +/- abdominal pain is present
  • Chronic diarrhea – May include a more extensive workup:
  • Radiographs
  • Abdominal ultrasound
  • Diarrhea panel PCR including B12, folate, TLI
  • Endoscopy +/- colonoscopy with biopsy


You can often manage mild dog diarrhea treatment at home, so here’s a plan for diarrhea days.

First, you want to be sure your dog has access to fresh, filtered water so that he/she does not become dehydrated.

Fasting for 6-12 hours is recommended to allow the intestinal tract to rest and give the gut time to heal.
It is not recommended to fast a puppy, a very small dog or an elderly dog.

Dr. Loudon’s magic diarrhea recipe: Feed cooked sweet potato, 1 tsp plain psyllium husk per 10 lbs and warm water for the next 1–2 meals depending on severity of diarrhea. Next add in a bland meat for the next 2–3 meals. Once the stools become formed, you can slowly switch back over to the maintenance diet over the next 3–4 meals.

Probiotics: A soiled-based probiotic with multiple species is a great choice. I like protect from fourleafrover.com. Raw goat’s milk is another great way to provide probiotics for your dog. The probiotics prescribed by vet offices are often poor quality and lack high numbers of diverse species of bacteria. Prebiotics are complex carbohydrates, like fructo-oligosaccharides, lactulose, and lactosucrose, that increase growth of beneficial intestinal bacteria and improve barrier function. These work synergistically with probiotics, and most high-quality probiotic supplements will have both.

Metronidazole: This medication is frequently prescribed by veterinarians, however, recent studies have shown that its deleterious effects on the gut flora do not recover until weeks after administration. If your vet prescribes this, you may want to ask if it is absolutely necessary.

If your dog is losing a moderate amount of fluids through severe diarrhea, then fluid therapy may become necessary.

Treatments will be targeted for specific causes such as exocrine pancreatic insufficiency, organ dysfunction, hypoadrenocorticism, etc.

Diarrhea is always inconvenient for us and can cause discomfort for your dog. As dog guardians, we will have to deal with it at some point.

If you feed your dog a varied, whole food diet and a daily probiotic, you will hopefully have to deal with it less often.

When it does occur, follow these guidelines, and you should be able to get it under control very quickly. If it doesn’t improve within 48 hours, then it may be a symptom of something more serious.

Here’s to less bouts of diarrhea in your dog’s future!