Dog Diarrhea – Causes, Care & When to Call the Vet

This information is for general guidance only. Always consult your veterinarian for specific advice about your dog’s health.

What is diarrhea?

Diarrhea means loose or watery stools passed more frequently than normal. Healthy dog stool should be firm and easy to pick up. When stool becomes soft, loose or liquid and the frequency increases, your dog has diarrhea. Veterinarians categorize diarrhea as large bowel (arising from the colon) versus small bowel (arising from the small intestine); most acute episodes involve the large bowel and resolve with minimal treatment.

Common causes

Diarrhea is a symptom of many different issues. Common triggers include:

Dietary indiscretion: Eating rich or unfamiliar food, getting into the garbage or ingesting toxic foods like chocolate.
Sudden diet changes: Switching your dog’s food too quickly can upset their gastrointestinal tract.
Stress: Emotional stress can upset digestion in dogs.
Infectious diseases: Viral illnesses such as parvovirus or canine distemper can cause diarrhea.
Internal parasites: Giardia, hookworms, roundworms, coccidia and whipworms are all parasites that can lead to diarrhea.
Food allergies or intolerances: Some dogs react poorly to certain ingredients.
Medications and medical conditions: Some medications and conditions like pancreatitis can cause diarrhea.

Symptoms

Signs of diarrhea include watery or soft stools, increased frequency, straining to defecate, gas, abdominal cramps and occasionally vomiting. Black, tarry or bloody stools are red flags that warrant immediate veterinary care.

Gentle home care

Most mild cases resolve on their own. If your dog is otherwise bright and eating, you can:

Withhold food for 12–24 hours to rest the gut, while ensuring plenty of fresh water.
After the fast, feed a bland diet such as boiled chicken or lean hamburger mixed with white rice in small meals for two to three days.
Gradually reintroduce your dog’s regular food over several days.
Maintain hydration – offer ice chips or small amounts of water frequently. Puppies, seniors and small dogs dehydrate quickly.

When to call the vet

Seek veterinary care if your dog’s diarrhea:

Contains blood or looks tarry (black).
Is accompanied by vomiting, a lack of appetite or lethargy.
Persists longer than 24–48 hours or occurs off and on for several days.
Occurs in a puppy, senior dog or a dog with existing health conditions.

Diarrhea can lead to dehydration and may indicate a serious underlying condition. Always call your vet if you are concerned.

Preventive tips

Transition your dog’s food gradually over 7–10 days.
Keep garbage and toxic foods out of reach.
Keep vaccinations and parasite prevention up to date.
Avoid sudden stress by introducing changes to routine slowly.