A dog with both vomiting and diarrhea at once loses fluid fast from both ends, which makes it more concerning than either alone. Knowing the danger signs tells you whether to watch or to go.
Vomiting and diarrhea together in a dog often comes from dietary indiscretion, a bug, stress, or a more serious illness, and the combination risks dehydration quickly. Watch closely, keep water available, and withhold food only briefly if advised. See a vet promptly for blood, repeated episodes, lethargy, a bloated belly, or if it lasts beyond a day, and sooner in puppies and seniors.
About Cerenia (maropitant): this is a prescription medication your veterinarian can prescribe. Read our guide, or ask us if you need help sourcing it.
Common causes
Dietary indiscretion (garbage, table scraps, a diet change), viral or bacterial infections, intestinal parasites, stress, or a more serious underlying illness. Puppies with both signs raise concern for parvovirus, which is an emergency. [1]
What you can do at home
For a mild single episode in a bright dog, keep fresh water available and follow your vet's guidance on brief food rest and a bland diet. Do not use human anti-diarrheal or anti-nausea medications without veterinary direction; some are unsafe for dogs and it's not the right call to guess.
When to see a vet
Go promptly for blood in vomit or stool, repeated or non-stop episodes, lethargy or weakness, a swollen or painful belly, signs of dehydration, or if it continues beyond about 24 hours. Puppies and seniors have less reserve, so don't wait as long.
How vets help
Beyond treating the cause and rehydrating, a vet may prescribe an anti-nausea medication like Cerenia, or an antibiotic such as metronidazole for certain GI infections. These are prescription decisions; when a vet prescribes one, we can supply it after review.
Frequently asked questions about dog vomiting and diarrhea
Should I withhold food from a vomiting dog?
A brief rest can help mild cases, but follow your vet's advice, and don't withhold water. Puppies shouldn't be fasted long.
When is vomiting and diarrhea an emergency?
Blood, repeated episodes, lethargy, a bloated belly, or signs in a puppy (possible parvo) mean go now.
Can I give my dog Imodium or Pepto?
Not without a vet, some human GI medications are unsafe for dogs.
Related digestive & nausea guides
Dog Nausea · Dog Vomiting · Dog Throwing Up Blood · Dog Throwing Up White Foam · Dog Throwing Up Yellow · Dog Diarrhea
Sources & References
For educational use. PrepperPetSupply is a licensed, veterinarian-staffed pharmacy; prescriptions are dispensed only after review by a licensed veterinarian and are not a substitute for in-person veterinary care. Not for human use.