Dog Diarrhea: How Serious Is It and What Should You Do?

Common Causes

There are many possible reasons a dog develops diarrhea:

• Diet: Eating something that doesn't agree with them, switching foods too quickly, or overeating
• Stress: A change in environment, boarding, or moving house
• Parasites: Giardia, roundworms, hookworms, and whipworms are common culprits
• Infection: Viruses such as parvovirus, bacteria like Salmonella or Campylobacter, or intestinal parasites
• Food allergies or intolerances
• Medication side effects — particularly antibiotics, which can disrupt gut flora
• Underlying illness: Pancreatitis, inflammatory bowel disease, tumors, and others

When You Can Monitor at Home

• Just one or two soft stools, with things back to normal shortly after
• Energy and appetite seem completely normal
• Happened right after switching to a new food — still in the adjustment window
• Stools are slightly soft but there's no blood or mucus

Home care tips:

1. Withhold food for 12–24 hours (adult dogs only — don't fast puppies for extended periods)
2. Make sure fresh water is always available to prevent dehydration
3. When reintroducing food, start with something bland: boiled chicken breast and plain white rice
4. Feed small amounts more frequently and monitor for 2–3 days

Checking for dehydration: Gently pinch a fold of skin at the back of your dog's neck or between the shoulder blades. If it springs back quickly, your dog is well hydrated. If it returns slowly or stays "tented," your dog may be dehydrated — see a vet.

When to See a Vet Right Away

• Diarrhea continues for more than 24 hours
• Stools contain fresh blood or appear black and tarry
• Vomiting alongside the diarrhea
• Your dog seems very lethargic, weak, or unwell
• Your dog is a puppy or senior (higher risk of rapid dehydration)
• You suspect they may have eaten something toxic
• Suspected parvovirus in an unvaccinated dog (symptoms: bloody diarrhea, severe vomiting, high fever)