Skip to main content

Why does my dog have diarrhea? (and when it’s time to see the vet)

Your dog has the runs — should you run to the vet?

Valeriia Miller / Pexels

Being a dog parent can be a joyful experience — no matter what your boss thinks of you, you can count on your pup to show you affection when you walk in the door. In exchange for their unconditional love and affection, dogs require that we take care of them and — sigh — pick up their poop (your neighborhood’s code enforcement requires the latter, to be more precise). Cleaning up after a dog also gives pet parents a role they may not have expected when they brought their furry friend home: Poop inspector.

Poop is a sign of a dog’s overall health. Regular, firm stool that resembles a caterpillar is one sign your pup is feeling well. If the stool is loose, you may need an answer to the question, “Why does my dog have diarrhea?” That depends. While we can’t answer the question definitively, we can provide some common causes of diarrhea and what to do.

sick brown puppy sitting by hose
Brixiv / Pexels

Why does my dog have diarrhea?

We can’t tell you for sure. However, diarrhea occurs when a dog’s fecal movement moves through the intestines more quickly, and their body absorbs less water, electrolytes, and other nutrients. The result? Loose stools. Sometimes, a dog’s diarrhea can be completely liquid.

Gross? Yes, but it is true — dealing with doggie diarrhea is part of the nature of dealing with the (lovably) beasts. Understanding the cause of your dog’s diarrhea will help you (and their vet) help them. There are several potential reasons a dog might have diarrhea, including:

  • Ingesting something toxic. Some foods (such as chocolate and garlic), plants, and household items are toxic to dogs. However, your pup doesn’t know that, and curiosity and their natural food drive might get the best of them.
  • Diet changes. If you recently changed your dog’s diet, their stomach may have trouble adjusting. Go slowly.
  • Food intolerances or allergies. Sometimes, a dog is allergic to their food. Other times, the food may be too hard on their stomach, even if no allergy is present.
  • Bacterial infections. Infections like salmonella can cause diarrhea in dogs.
  • Viral infections. Pups can get coronaviruses, too. These infections, along with others like parvovirus, can trigger poop problems.
  • Parasitic infection. Other parasites, like hookworm and ringworm, can invade a pup’s body and affect the stomach, including causing diarrhea.
  •  Stress. Has stress ever caused your stomach to feel like it’s in knots? Ditto for dogs. Remember, dogs can get emotional, too. Stress from travel or even a trip to the vet might upset their tummy.
  • Reactions to medications. If a dog is having trouble tolerating a medication, their body might show you through their poop.
  • Inflammatory bowel disease. Like humans, dogs can experience inflammatory bowel disease, and loose stools are a red flag.
  • Organ dysfunction. In more severe cases, a dog’s diarrhea can be a symptom of kidney and liver disease.
  • Cancer. Sometimes, poop can be a flag your dog has cancer, including in the stomach.
golden retriever looking sad lying on the floor
Bruno Cervera / Pexels

What to do if your dog has diarrhea

The good news is that diarrhea often resolves and has a mild cause. While the issue can be gross and uncomfortable, the prognosis is generally good. However, as you can tell, there are many reasons for doggie diarrhea. Only your dog’s vet can diagnose the cause of the diarrhea. If the regular veterinarian can’t, they can refer you to someone who can. You should always feel comfortable calling your dog’s vet — they’re here to help. However, you’ll want to get a professional on the line if your pet’s diarrhea hasn’t cleared up in two days. Additionally, call a vet if the diarrhea is accompanied by:

  • Blood in the stool
  • Black or tarry poop
  • Vomiting
  • Lethargy
  • Lack of appetite lasting more than two days or a refusal to drink water

Your dog’s vet can run tests, including bloodwork and x-rays, to determine the cause of the diarrhea and help your pet get back to normal. Common treatments include medication, a bland diet, and food switches.

A black and white dog outside
Dids / Pexels

Closing thoughts

Dogs get diarrhea for many reasons, and the issue is often treatable with diet and medication. Common causes of diarrhea in dogs include infections, consuming something toxic, food intolerances and allergies, and inflammatory bowel disease. Sometimes, diarrhea can be a sign of something more severe, like cancer.

You should feel comfortable calling your dog’s veterinarian with any concerns. However, you’ll want to get the vet on the line if a dog’s diarrhea hasn’t improved after two days. A vet can take bloodwork and x-rays to find the precise cause of your pet’s poop problems and prescribe the correct treatment.

BethAnn Mayer
Beth Ann's work has appeared on healthline.com and parents.com. In her spare time, you can find her running (either marathons…
Can dogs eat pears? What you need to know
Here's the truth and what to do if your dog eats pears
Bernese mountain dog with a par in his mouth

"Eat your fruits and veggies" is standard advice from doctors, dietitians, and parents — you may have been on the receiving end of this (sound) recommendation for your overall health. However, dog-specific food is generally limited to "dry" and "wet." That doesn't mean a taste of a favorite human food here and there is off the table. Still, you'll want to know which ones (blueberries and apples) are safe and which (chocolate, grapes, and onions) are off the table.

If you find pears peachy, you may wonder if you can share. Can dogs eat pears? What happens if the little rascal eats a piece of pear you dropped on the floor faster than you can say, "Leave it?" Good news: You don't have to panic. Here's what to know about pears and dogs.
Can dogs eat pears?

Read more
Why your dog barks in their sleep (and what you should do about it)
Here's why dreams make your dog vocal in their sleep
A close-up of a gray dog with a wrinkly nose sleeping on the floor

Whether you're relaxing on the couch or sleeping in the middle of the night, a sudden bark from your normally quiet dog could send you into a panic. Is there an intruder in your home? Is your dog frightened or in pain? You'll be relieved to know that none of these scary what-ifs are behind your pup's nocturnal noises. They're just a dog barking in sleep mode.
Hearing a dog barking in their sleep can be startling at first, even if you can see exactly what's going on, but many dog owners quickly learn that this is neither uncommon nor worrisome. Many dogs bark, whine, and groan in their sleep, though it's only normal to have questions about this unusual behavior. Luckily, we've got all the answers you need right here.

Why do dogs bark in their sleep?

Read more
Why do dogs lick each other? Some of the reasons might surprise you
For the most part, you don't need to worry about your dog licking their bestie
One Alaskan malamute licking another

Getting doggy kisses must be one of the best parts of pet ownership. While some pooch parents decide not to allow face licks, all these behaviors come from a place of love — it's one of the best ways your dog knows to say how much they appreciate you being their mom or dad. But why do dogs lick each other? The reasons can vary quite a bit, though they're mostly all harmless (we'll cover when you should be concerned and talk to the vet). This is what you need to know about your buddies licking each other.
Why do dogs lick faces?

It's not just that pup pups enjoy licking; they particularly go for faces, ours and other canines. When our buddies are little, their moms give them dog kisses to help them learn to potty and keep them clean. However, you may find it odd to discover your pet excessively licking another dog's face. Sometimes, they do this for the same reason as any other licks, but there can be a few extra motivating factors.

Read more