Health & vet care
Puppy Diarrhea: Causes and When to Call the Vet
Puppy diarrhea is common and often comes from a food change, stress or eating something they should not, but young puppies dehydrate quickly and some causes, such as parasites and parvovirus, are serious. Call your vet the same day if your puppy has not finished its vaccines, if diarrhea lasts more than a day, or if there is blood, vomiting, lethargy or loss of appetite.
By Matt GarnettUpdated November 9, 20264 min read3 sources
What puppy diarrhea usually means
Roughly from most to least common, the usual causes are a sudden change of food or too many new treats; stress from moving to a new home, travel or a change in routine; scavenging, when puppies eat trash, sticks, grass, other dogs' poop or bird droppings; and intestinal parasites such as roundworms, hookworms, whipworms, coccidia and giardia, which are extremely common in young puppies.
Less common but more serious are infections, including bacteria such as Salmonella and Clostridium and viruses such as parvovirus and distemper, which mainly threaten puppies who are unvaccinated or only part way through their shots. Swallowed toxins or objects that block the gut, and food intolerance, round out the list. Diarrhea is a sign, not a diagnosis, and only a vet can tell which of these is behind it.
When to call your vet today
Call your vet the same day if your puppy has not completed its vaccine series, since the AKC advises letting the vet decide about any diarrhea in an incompletely vaccinated puppy. Also call if diarrhea has lasted more than about 24 hours, if it keeps coming back, if your puppy is also vomiting, if they are eating less than usual, or if you see worms in the stool.
Other reasons to call today include a puppy who seems quieter or more tired than normal, a tender or bloated belly, mucus with streaks of blood, or a toy breed or very young puppy of any size with more than a couple of loose stools. Small puppies have little reserve, and dehydration and low blood sugar can set in within hours.
When it's an emergency
Go to your vet or the nearest emergency vet straight away for bloody or watery diarrhea that will not stop, black, tarry stool, repeated vomiting, a puppy who is weak, floppy or hard to wake, pale or gray gums, a fever, or obvious pain. These signs together, in a puppy who has not finished its shots, are a classic picture of parvovirus, which needs urgent hospital care.
Also treat it as an emergency if you think your puppy has swallowed something toxic or an object such as a sock or toy. If poison is possible, call your vet, or the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661; a fee may apply.
What you can safely do at home
For a bright, playful puppy who is eating, drinking and not vomiting, with no blood in the stool, a short period of careful watching is reasonable, with a call to your vet for advice. Keep fresh water available at all times in a sturdy dog water bowl, note how many loose stools there are and what they look like, and take a photo; it helps your vet more than you might think.
Do not give any human medicines, anti-diarrheal tablets, or leftover pet medications, and do not start a home-cooked diet on your own. VCA notes that many vets now recommend a short course of a specific veterinary diet rather than the old chicken-and-rice approach, so ask what your vet prefers. When stools are back to normal, mix the usual food back in gradually over several days.
What the vet will likely check
Expect questions about diet changes, treats, anything your puppy might have eaten, vaccination and deworming history, and how often and what the diarrhea looks like. The vet will check hydration, gums, temperature and belly, and weigh your puppy to compare with previous visits.
A fecal test is the most common first test, since parasites are such a frequent cause; bring a fresh sample in a sealed bag if you can. Depending on the findings, your vet may run a parvovirus test, blood work, or X-rays if a blockage is suspected. Treatment depends on the cause and may include a dewormer, a bland veterinary diet, fluids, or hospital care for severe cases.
Preventing diarrhea in puppies
Change foods slowly over 7 to 14 days, and keep treats small and consistent. Keep trash, food scraps and small objects out of reach, and use a crate or pen when you cannot supervise. Follow your vet's deworming and vaccine schedule closely, since parasites and parvovirus are the most preventable serious causes.
Until the vaccine series is complete, avoid dog parks, pet store floors and other areas used by unknown dogs, and pick up after your own puppy promptly with dog poop bags. Watching your puppy's stool every day is one of the easiest ways to notice a problem early.
This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.
Common questions
How long does puppy diarrhea last?
Mild diarrhea from stress or a diet change often settles within a day or two. If it lasts more than about 24 hours, keeps coming back, or comes with other signs, call your vet rather than waiting.
Is it normal for a new puppy to have diarrhea?
Loose stool in the first few days in a new home is common, from stress and a change of food. It still deserves a call to your vet, especially if the puppy is not fully vaccinated.
Can teething cause diarrhea in puppies?
Teething itself is not a proven cause, but teething puppies chew and swallow more things they should not, which can upset the stomach. Any ongoing diarrhea should be checked rather than blamed on teething.
What color poop is a concern in a puppy?
Black and tarry, red or bloody, gray and greasy, or with white specks that could be worms all need a vet check. Normal puppy stool is brown and formed.
Sources we checked
This guide is general information, not veterinary advice. If your pet is unwell or injured, contact your veterinarian.
