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.

Editors' Recommendations

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…
Are Himalayan dog chews safe for your pet? Know this before you buy
These dogs treats are still trendy but should probably be eaten in moderation
A close-up shot of a pug standing in the grass with a bone-shaped treat in his mouth

What do blueberries, kale, and broccoli all have in common? In addition to being delicious, all three are part of the group of so-called superfoods. Unfortunately, there's no federally regulated definition for the term, but Harvard scientists claim food that "offers high levels of desirable nutrients, is linked to the prevention of a disease, or is believed to offer several simultaneous health benefits beyond its nutritional value" can be labeled superfoods. 

Just like you might add chia seeds to your granola or spirulina powder to your smoothies for additional vitamins and minerals, you also want to make sure your dog's food and treats pack a beneficial wallop. Made famous on Shark Tank, Himalayan dog chews have become one of the most hotly debated treats in the pet food game, which begs the question, "Are Himalayan dog chews as healthy as some people think?"

Read more
Can dogs eat mango? Read this first
Find out if this tropical fruit is safe for your pup
A dog in the kitchen looking up at woman drinking coffee

As humans, we love to share with our dogs. Perhaps your pet snuggles up to you in bed, sharing — or stealing — your blankets. Sharing experiences, like holiday activities, can also be a fun way to bond.

Food can get dicier, though. Some human-favorite items, like chocolate, are toxic for dogs. Others make fine (and even healthy) treats. If mango is your favorite fruit, you might want to slip your pet some. Also, your dog might always be around the fruit and sneak some off your plate. Can dogs eat mango safely? Generally, the answer to this question is yes, but there are some caveats. Also, correctly serving a mango is critical. Before throwing your dog a piece of this sweet fruit, here's what to know.

Read more
Can dogs eat celery? The do’s and don’ts you should know
Your pup will probably love a veggie snack now and then
Woman chops up veggies including celery for her dog

Your dog's favorite snacks might include dog biscuits, fancy chews, or even that bacon you dropped on the floor one time, but can dogs eat celery? The truth is lots of dogs like veggies, even bland ones such as celery. While you wouldn't want this green and healthy nibble to become a staple in their diet, you can absolutely give your pup a celery snack now and then — and they might grow to love it.

Can dogs have raw celery?
As omnivores, our pet dogs need a balanced diet of both meat and plants. That's likely because their domestic history made them into scavengers thousands of years ago when our ancestors were still in the hunter-gatherer phase. In modern times, this diet preference has huge benefits because you can throw in some healthful treats that will give your pup a nutrition boost and keep them full.

Read more