Diarrhea is one of the most common reasons dog owners call the vet. The good news is that most cases are mild and resolve on their own. The key is knowing what's causing it and recognizing when it's something more serious.
The Most Common Causes
Dietary indiscretion — Your dog ate something they shouldn't have. Garbage, table scraps, a dead bird in the yard, another dog's food. This is by far the most frequent cause and usually passes within a day.
Food changes — Switching food too quickly is a classic trigger. A dog's gut needs 7 to 10 days to adjust to new food. Always transition gradually by mixing increasing amounts of the new food with the old.
Stress — Boarding, travel, a new pet, moving, or even a change in routine can cause stress-related diarrhea. It typically resolves once the dog settles.
Parasites — Roundworms, hookworms, giardia, and coccidia are all common in dogs, especially puppies. If your dog has recurring diarrhea or you see anything unusual in the stool, a fecal test from your vet can identify the culprit.
Infections — Bacterial infections (like salmonella) or viral infections (like parvovirus) cause diarrhea along with other symptoms. Parvo is especially dangerous in unvaccinated puppies.
When It's Serious
Most diarrhea clears up in 24 to 48 hours. But get to a vet promptly if you see:
- Blood in the stool — bright red or dark, tarry stools
- Diarrhea lasting more than 24 hours in a puppy or senior dog
- Diarrhea lasting more than 48 hours in an adult dog
- Vomiting alongside diarrhea — dehydration risk increases fast
- Lethargy, refusal to eat, or fever
- Signs of pain — whimpering, hunched posture, reluctance to move
Puppies and senior dogs dehydrate quickly, so err on the side of caution with them.
The Bland Diet Protocol
For mild cases in otherwise healthy adult dogs, vets commonly recommend a temporary bland diet:
- Boiled chicken (boneless, skinless) mixed with plain white rice in a 1:2 ratio
- Feed small, frequent meals — 3 to 4 times per day
- Continue for 2 to 3 days after stools firm up
- Gradually reintroduce regular food over 5 to 7 days
Make sure fresh water is always available. You can also add a small amount of plain canned pumpkin (not pie filling) — it's gentle on the stomach and adds fiber.
What to Avoid
Don't give your dog over-the-counter human anti-diarrheal medications like Imodium without vet guidance. Some breeds (especially herding breeds with the MDR1 gene mutation) can have serious reactions to these drugs.
Preventing Future Episodes
Keep garbage secured, avoid sharing fatty or seasoned human food, stay current on parasite prevention, and transition food slowly. A daily probiotic formulated for dogs can also help maintain gut health.
On Mylo, dog owners share what's worked for their pets' digestive issues — from specific bland diet recipes to probiotic brands recommended by their vets. When your dog's stomach is off, it helps to hear from others who've been through it.