Dr. Tiffany Delacruz, DVM • Chief Executive Officer, RexVet • 2026-07-01 • 11 min read
Dog Diarrhea: Causes, Home Care & When to Call a Vet — FL, NY & VA Guide
Dog diarrhea has 8 common causes — dietary indiscretion, parasites, stress, food change, giardia, IBD, pancreatitis, and infection. FL/NY/VA licensed vets triage and treat by $64.99 video.
Medically reviewed by Dr. Tiffany Delacruz, DVM
Dog diarrhea is the #1 reason pet parents call the vet. Most cases resolve on their own within 48 hours, but a subset are early signs of serious disease — parvovirus in puppies, pancreatitis in adults, HGE at any age. This guide is written for dog parents in Florida, New York, and Virginia and walks through how to triage at home, when to call a vet, and how telehealth fits.
The 8 common causes
- Dietary indiscretion — garbage, table scraps, sudden fatty meal, treats overdose. Most common cause overall.
- Abrupt food change — switching kibble without a 7-day transition. Extremely common and preventable.
- Stress colitis — boarding, travel, thunderstorms, new household member. Often mucus and small amounts of blood.
- Intestinal parasites — roundworms, hookworms, whipworms, giardia, coccidia. More common in puppies and rescues.
- Viral infection — parvovirus (unvaccinated puppies, deadly), coronavirus, distemper.
- Bacterial — Salmonella, Campylobacter, Clostridium. Often from raw diet, uncooked chicken, contaminated water.
- Pancreatitis — fatty meal trigger, often holiday overindulgence. Vomiting + hunched posture + belly pain + diarrhea.
- Inflammatory Bowel Disease (IBD) — chronic intermittent diarrhea in adult dogs, often with weight loss. Diagnosis of exclusion.
Red flags — ER TODAY
- Puppy under 6 months with diarrhea + lethargy or vomiting — parvo screen
- Frank bloody diarrhea + vomiting + collapse — HGE emergency
- Black tarry stool (melena) — upper GI bleeding
- Diarrhea plus persistent vomiting — dehydration risk
- Diarrhea plus severe abdominal pain (hunched, won't lie down) — pancreatitis or obstruction
- Diarrhea lasting more than 72 hours in adult dog
- Any diarrhea in a diabetic, immunocompromised, or geriatric dog
Home care that works — first 24 hours
- Fast 12 hours (adults only, never puppies) then reintroduce food
- Bland diet — boiled chicken breast (no skin, no seasoning) + white rice, 1:2 ratio, small frequent meals
- Pumpkin puree (plain, not pie filling) — 1 tbsp per 20 lbs, mixed into food, helps normalize stool
- Probiotic — Fortiflora, Proviable, or Purina Pro Plan Veterinary FortiFlora, 1 sachet daily for 5 to 7 days
- Access to fresh water — do NOT restrict water
- Transition back to regular diet over 3 to 5 days once stool is formed
When over-the-counter Imodium is dangerous
Do not give human antidiarrheals without vet guidance. Loperamide (Imodium) is toxic to Collies, Australian Shepherds, and other herding breeds with the MDR1 gene mutation. It can also mask infectious diarrhea that needs treatment. Pepto-Bismol contains salicylates that cause GI ulceration in dogs and are dangerous in cats. Ask a vet before dosing any human medication.
Florida: parasites + heat + garbage
Florida's year-round warmth means intestinal parasites (hookworms, whipworms, giardia) are transmitted 12 months per year. Any FL dog with recurrent diarrhea should get a fresh fecal float + giardia antigen test. Beach dogs often ingest saltwater or dead fish — dietary indiscretion is the #1 FL summer trigger.
New York: stress colitis + city triggers
NYC dogs get more stress colitis than average — boarding during owner travel, apartment noise, thunderstorms in summer. City dogs also ingest sidewalk debris and rat bait — always check what your dog picked up. NY winter salt exposure causes paw irritation but can also cause GI upset if licked.
Virginia: tick disease + rural exposure
VA dogs with diarrhea plus lethargy plus tick exposure need Lyme, Ehrlichia, and Anaplasma testing (4Dx Snap) — these tick diseases cause GI signs. Rural VA dogs also encounter wildlife feces (raccoon, deer), garbage, and hunting scraps — high dietary indiscretion risk.
When telehealth fits — and when it doesn't
- Uncomplicated adult dog diarrhea, no red flags — telehealth works, bland diet + probiotic + recheck plan
- Food change or transition management — telehealth ideal
- Giardia treatment (fenbendazole + metronidazole) — telehealth with fecal in-person
- Chronic IBD maintenance — telehealth for refills and diet management
- Puppy under 6 months, ANY diarrhea — in-person for parvo screen + fecal
- Bloody diarrhea or black stool — in-person same day
- Vomiting + diarrhea + lethargy — in-person, dehydration risk
Emergency signals
When to contact a veterinarian
- Puppy under 6 months with diarrhea + lethargy or vomiting
- Frank bloody diarrhea or black tarry stool
- Diarrhea + persistent vomiting or collapse
- Diarrhea + severe abdominal pain (hunched, won't lie down)
- Diarrhea lasting more than 72 hours in an adult dog
- Any diarrhea in a diabetic, immunocompromised, or geriatric dog
Frequently asked questions
How long can dog diarrhea last before I call a vet?
Adult dog with normal energy and appetite: 24 to 48 hours of home care with bland diet and probiotic is reasonable. Any longer, or if new symptoms appear (vomiting, lethargy, blood, appetite loss), call a vet. Puppies always sooner — same day if lethargic or vomiting.
Can a RexVet online vet help with my dog's diarrhea?
Yes for uncomplicated adult dog diarrhea, food transition guidance, giardia treatment planning, IBD maintenance, and probiotic and diet recommendations. $64.99 video visits with FL/NY/VA licensed vets. Puppies with diarrhea, bloody stool, or dogs with vomiting plus lethargy need in-person care.
What can I give my dog for diarrhea at home?
Bland diet (boiled chicken and white rice, 1:2 ratio), plain pumpkin puree (1 tbsp per 20 lbs), and a canine probiotic like Fortiflora. Access to fresh water at all times. Avoid human antidiarrheals like Imodium unless your vet directs — some breeds have dangerous reactions.
When is dog diarrhea an emergency?
Puppy diarrhea plus lethargy or vomiting (possible parvo). Frank bloody diarrhea plus vomiting or collapse (possible HGE). Black tarry stool (upper GI bleeding). Diarrhea plus severe abdominal pain. Diarrhea in a diabetic, geriatric, or immunocompromised dog. These need same-day in-person care.
Should I fast my dog if they have diarrhea?
Adult dogs: a 12-hour fast then a bland diet is fine. Puppies: never fast, they have low blood sugar reserves. Diabetic dogs: never fast without vet guidance. Always allow access to water regardless.
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About the author
Dr. Tiffany Delacruz, DVM
Chief Executive Officer, RexVet
Licensed veterinarian and CEO of RexVet (Rex Vets Inc.). Practicing across Florida, New York, and Virginia via licensed telehealth. Reviews every clinical article on RexVet before publication.