Author TB Thompson DVM has been a licensed, practicing veterinarian since 2000.

Got a dog with diarrhea but is acting normal? It’s a common issue that can have many causes, from bad food to parasites.

But don’t ignore this symptom. If the diarrhea lasts more than 48 hours or if your pup shows other signs like not eating or vomiting, it’s vet time.

In this article, we’ll explore the reasons this happens and when you should have your dog see a veterinarian.

KEY POINTS

  • Diarrhea is one of the most common health issues in dogs and can be caused by many things from dietary indiscretion to serious systemic disease.
  • Most mild cases of dog diarrhea resolve without specific treatment within 48 hours.
  • Rest, a bland diet and close monitoring are recommended for all early cases of diarrhea in dogs. 

Why do dogs act normal when they have diarrhea?

Diarrhea, by definition, is a condition in which feces contain more liquid than normal. You might see mushy poo or completely liquid stools and everything in between. 

Mild cases of diarrhea in dogs may not cause enough discomfort for them to show outward signs of illness. Animals tend to hide mild illness as an instinctual survival mechanism. 

Dogs with more severe cases usually show some outward symptoms early on, presumably from intestinal cramping pain. As diarrhea persists past 24 hours, dehydration and electrolyte deficiency can develop. These dogs often suffer from lethargy, vomiting and poor appetite. 

Symptoms

There are two types of diarrhea that occur in dogs: large intestine diarrhea is the most common while small intestinal diarrhea occurs less frequently. Let’s look at the symptoms of each form. 

Large Intestine Diarrhea

Large intestine acute diarrhea (colitis) occurs when food moves through the lower part of a dog’s bowel too quickly. The large intestine doesn’t absorb water fast enough, so it’s passed in the feces.

  • Mucus in stool-this looks like clear or tan jelly which might look like it’s encasing the dog’s poop
  • Bloody stool (streaks of blood are common, larger amounts where it looks like strawberry jam may be hemorrhagic gastroenteritis)
  • Straining to pass small amounts of stool
  • Increased frequency and urgency to poop
  • Pacing, can’t get comfortable
  • Decreased appetite (complete lack of appetite is more serious)
  • Lethargy, irritability
  • Trembling or shaking
  • Noise from guts
  • Passing gas
  • Scooting bottom on the ground due to anal irritation from watery diarrhea
  • Poop accidents inside the house due to increased urgency

Small Intestine Diarrhea

Diarrhea can be caused by problems in different parts of the gut. If it’s happening in the small intestine, it might not have the same symptoms as diarrhea in the large intestine. 

Dogs with small intestine diarrhea may have softer poop, but they still go as often as usual. They might also be making more poop than usual. In the early stages, dogs with this kind of diarrhea might act completely normal.

This type of diarrhea can last a long time and cause your dog to lose weight. On the other hand, large intestine diarrhea usually won’t make your dog lose weight. It’s important to see a vet if your pup has symptoms of small intestine diarrhea.

Causes of diarrhea in dogs

Dietary Indiscretion 

Dogs love to eat things they’re not supposed to! Vets sometimes call the results “garbage gut.” When dogs eat something they shouldn’t, like garbage, rotten food or dead animals, it can make them have diarrhea. This is the most common reason that dogs get diarrhea. So, if your dog has diarrhea, the first thing to ask yourself is whether they could’ve eaten something they shouldn’t have.

Stress and Anxiety

Stress and anxiety cause hormonal and neurological stimulation of the GI tract. There are a lot of things that can stress out a dog enough to cause diarrhea. 

Some examples include separation anxiety, visiting the grooming shop, staying at a boarding kennel, visitors or workers in the home, traveling and going to the vet clinic. All of these things can stress a dog enough to mess up their normal digestion.

Stress-related diarrhea can happen quite suddenly. I’ve known dogs who routinely started having diarrhea as soon as they arrived at a boarding kennel, even before their owner left the building! 

Viral and Bacterial Infections

Viruses and bacteria can also make dogs have diarrhea. Common viral causes of loose stool include parvovirus, coronavirus and distemper virus. Viral diarrhea occurs more often in unvaccinated puppies after exposure to infected dogs or their fecal matter.

Bacterial infection of a dog’s GI tract can cause diarrhea. Some of the common players include Salmonella, Campylobacter, E. coli, and Clostridium. These bacteria can come from other animals, food, garbage, or the environment. (1)

Parasites

Parasites are microscopic organisms that can make dogs sick when they infect their digestive system. Hookworms, roundworms, whipworms, and Giardia are common canine parasites that can all cause diarrhea. 

Puppies are more likely to get infected with parasites than adult dogs. But adult dogs can also get sick from parasites, especially if they’re housed in a very contaminated area. Parasites are often spread from dog to dog when they accidentally eat poop during grooming or feeding. Dogs who regularly come into contact with other dogs have a higher risk of parasitic infection.

GI and Other Systemic Diseases

One study found that inflammatory disease was the most common primary cause of diarrhea in dogs. (2) A common cause of inflammatory GI disease is food intolerance. This happens due to an inability to properly digest certain foods, leading to digestive symptoms. Sometimes, it is caused by an allergic reaction to a food ingredient but food allergy is less common than food sensitivity. 

Systemic diseases like kidney disease, liver disease, pancreatitis, inflammatory bowel disease and cancer can cause secondary diarrhea in dogs. These conditions affect different organs of the body but can result in changes to digestion. Most dogs with one of these problems have other symptoms but for some, diarrhea might be the only obvious thing that’s abnormal. 

Home care

If your dog has diarrhea but is acting normal in every other way, you may choose to wait and see what happens for the next 24-48 hours. Most mild cases of diarrhea in dogs resolve without specific treatment within this time frame.

Some more important tips

  • Avoid treats, rich table food and new dog food.
  • Skip one meal to let the digestive tract calm down. Do not withhold water.
  • Feed a diet of mushy white rice and boiled chicken breast (or cooked ground turkey) for 24-48 hours
  • Have your dog rest, avoiding exercise until stool firms up.
  • See a veterinarian if diarrhea lasts more than 48 hours. Remember to take a fresh stool sample from your dog to the vet clinic for analysis.
  • If your dog has a poor appetite, vomiting, lethargy or lots of blood in their stool, seek care from a veterinarian immediately. 

Remember that it’s never wrong to consult your veterinarian even if you think your dog is doing OK. Express your concerns and have the vet look your dog over to check for more serious problems.

Homemade “Bland” Dog Food Recipe 

After withholding one meal from your dog, start with a very simple, low-fat, bland diet. Try this easy homemade recipe for a few days. It’s not a balanced diet, so don’t feed it long-term.

chicken and rice meal for dogs (for when a dog has diarrhea but is acting normal)

Turkey or Chicken & Rice Recipe for Dogs with Diarrhea

Serving Size: about 8 for medium dog • Time: 45 minutes • Difficulty: Easy

Ingredients

  • 1 cup white rice
  • 6 cups water
  • 2 pounds lean ground turkey (85% lean or leaner) or chopped boneless/skinless chicken breast

Directions

  1. Place water and rice into a large pot and bring to boil over medium heat.
  2. Reduce heat to low and simmer rice for 15 minutes.
  3. Add ground turkey or chopped chicken breast to rice, breaking it up with a spoon.
  4. Cook over medium-low heat for another 20-30 minutes, stirring occasionally until rice is very mushy and turkey/chicken is cooked through (no pink). You can add more water if it looks too dry. The goal is to have a stew consistency with the rice mostly broken down and mushy.

How Much to Feed

  • small dog about 1/4–1/2 cup
  • medium dog 1/2–1 cup
  • large dog about 1–2 cups

Feed this amount twice a day for 2–3 days.

When should my dog see a veterinarian?

With diarrhea being such a common problem, it’s sometimes hard for dog owners to know whether the situation is an emergency or not. So I’ve laid out a list of signs that a dog with diarrhea needs emergency care…

Summary

Diarrhea is a common issue for dogs and can be caused by a range of factors, such as eating spoiled food, viral infections, or parasites. Dogs with mild cases of diarrhea may not exhibit any symptoms, but dogs with more severe cases often show symptoms such as vomiting, lethargy, and poor appetite. 

The two types of diarrhea in dogs are large intestinal diarrhea and small intestinal diarrhea, each with different symptoms. In order to prevent future instances of diarrhea, owners should keep an eye on their dog’s diet and stress levels. If a dog’s diarrhea lasts more than 48 hours or if they exhibit other symptoms, a visit to the vet is recommended.

Read a Related Post

  1. Marks, S. L., Rankin, S. C., Byrne, B. A., & Weese, J. S. (2011). Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment, and control. Journal of veterinary internal medicine, 25(6), 1195-1208.
  2. Volkmann, M., Steiner, J. M., Fosgate, G. T., Zentek, J., Hartmann, S., & Kohn, B. (2017). Chronic diarrhea in dogs–retrospective study in 136 cases. Journal of veterinary internal medicine, 31(4), 1043-1055.