Puppy Diarrhoea: Causes, Warning Signs and When to Call the Vet

Most puppies get diarrhoea at some point, usually from a change of food, stress or eating something they shouldn't, and many mild cases settle within a day or two. But puppies dehydrate quickly, so the safest rule is to ring your vet for advice whenever your puppy has diarrhoea. Call immediately if there is blood, vomiting, lethargy, refusal to eat, or if your puppy is very young or not fully vaccinated.

Is it really diarrhoea? Checking your puppy's poo

Diarrhoea (spelled diarrhea in American English) means loose, watery or unusually frequent poo. The Royal Kennel Club uses a stool chart that runs from a firm, well-formed log to a liquid puddle: a healthy puppy's poo should sit at about a 2, and a score of 4 or above counts as diarrhoea. Soft stools on their own can still matter: PDSA advises calling your vet if soft poo carries on for more than 24 hours.

When you clean up, take a quick look at what you are dealing with. Note the colour, how runny it is, how often your puppy is going, and whether you can see blood, mucus or worms. A small amount of mucus can be normal, and a single small streak of blood may not be serious, but larger amounts, red mucus or blood on more than one occasion all need a call to the vet. These details are exactly what your vet will ask about.

Common causes of diarrhoea in puppies

Diarrhoea is one of the most common reasons puppies are taken to the vet, and most puppies develop diarrhoea at some point early in life because they are so sensitive to change, stress and infection. The good news is that many cases of diarrhoea can be treated at home with your vet's guidance, but severe diarrhoea can make a puppy very unwell quickly. Possible causes include the following.

Some owners also notice loose stools during teething. The Royal Kennel Club suggests sore gums may cause stress, and that chewing on objects can irritate the stomach or pick up a mild infection. If it is severe or does not settle, speak to your vet.

When is puppy diarrhoea an emergency?

Treat diarrhoea in a puppy more seriously than diarrhoea in dogs that are fully grown. Blue Cross advises contacting the vet immediately for puppies because they can become dehydrated quickly, and PDSA notes that diarrhoea in a puppy can be more serious. Use the checklist below, and if you are unsure whether your puppy needs veterinary care, call and ask.

Contact a vet immediately if your puppy:

• has blood in their poo (more than a small streak, or more than once), black or tarry stools, or red mucus
• is vomiting as well; puppy vomiting more than once, or bringing up blood, needs urgent help
• is lethargic, weak, collapsed, very tired or seems hot
• won't eat or drink
• has severe, constant or very watery diarrhoea, or several bouts over a few hours
• has a painful or bloated tummy, is straining without passing anything, or has pale, blue or tacky gums
• may have eaten something toxic, or an object that could cause a blockage
• is not fully vaccinated and has diarrhoea with any of the signs above, as parvovirus is a real possibility
• is very young or very small, or has another health condition

Call your vet the same day for advice if:

• the diarrhoea has lasted longer than 24 hours; PDSA advises contacting your vet as soon as possible at that point
• your puppy seems bright but is still passing loose stools, or the diarrhoea is accompanied by other symptoms you are unsure about
• the diarrhoea started after a new medicine, worming treatment or vaccination and is not settling
• it keeps coming back, even if each episode is mild

If it happens out of hours, don't wait until morning to seek veterinary advice: phone your practice or your nearest emergency vet.

Puppy diarrhoea and parvovirus

Canine parvovirus is the infection every puppy owner should know about. It causes bloody, foul-smelling diarrhoea, vomiting, loss of appetite, fever, low mood and collapse, and it can kill. Puppies between six weeks and six months old and unvaccinated dogs are most at risk, and the virus spreads through poo and vomit, on bedding, bowls and even on people's shoes and clothes. It can survive outside the body, for example in park grass, for at least six months.

There is no drug that kills the virus. Treatment means supportive care in a hospital, such as intravenous fluids and anti-sickness medicine, and many puppies do not survive. Early treatment improves the outlook, so if you suspect your puppy has parvo, call your vet immediately and tell them before you arrive, so they can keep other dogs safe. Our guide to parvo in puppies explains the signs and the risks in more detail.

What to do at home if your puppy has diarrhoea

Speak to your vet first. If they are happy for mild diarrhoea to be treated at home, the steps below are what UK vet charities typically recommend. Keep a close eye on your puppy and call back if symptoms persist or anything changes.

• Keep water available. Fresh water should be on offer at all times, as dehydration is the main danger. If your puppy is reluctant to drink, the Royal Kennel Club suggests a little juice from tinned tuna (not tuna in brine) or ice cubes. If they are also being sick, offer small amounts of water often rather than a big drink.
• Do not starve a puppy. A short fast is sometimes suggested when an adult dog has diarrhoea, but PDSA says not to fast very young dogs, and the Royal Kennel Club warns that starving a puppy with diarrhoea could be dangerous because the gut needs food to repair.
• Feed little and often. Small, frequent meals are easier on the gut; the Royal Kennel Club suggests something like 6 to 8 small meals a day.
• Let them rest. Skip energetic play and long sessions until they have fully recovered.
• Stop the extras. No treats, chews, table scraps or rich food until stools return to normal.
• Keep things clean. Pick up poo promptly, wash bedding, clean with a pet-friendly disinfectant and wash your hands, as some causes, such as the giardia parasite, can spread to other dogs and to people.
• Save a sample. Ask your vet whether they want a stool sample. Double-bag it, and if your appointment is several hours away you can keep it in the fridge.

Accidents are likely while your puppy is poorly, so be patient and don't tell them off. Your normal routine for toilet training a puppy can resume once their poo is firm again.

Never give your puppy human medicines or anti-diarrhoea products unless your vet has told you to.

What to feed a puppy with diarrhoea

If your vet agrees, a short spell of bland food can help settle the gut. A bland diet is made of easily digestible food and is meant to be temporary.

Puppies need a balanced diet to grow, so a homemade bland diet should not go on for more than a few days without your vet's advice. Once their poo is firm, move them back to their normal puppy food gradually: Blue Cross suggests starting with a 50/50 mix of bland and normal food and increasing the normal food until the bland food is no longer needed, and PDSA suggests doing this over three to five days. If you are unsure how much to feed a growing puppy day to day, our puppy feeding guide covers portions and meal plans.

Call your vet if your puppy won't eat the bland food, doesn't improve, or needs it for longer than a few days.

Puppy diarrhoea treatment: what to expect at the vet

Veterinary treatment will depend on how unwell your puppy is and the likely cause of diarrhoea. Expect some or all of the following:

1. Questions. When it started, how often your puppy is going, what the poo looks like, what they have eaten, whether they could have scavenged anything, and their vaccination and worming history.
2. An examination. Checking hydration, temperature, gums and tummy.
3. Tests. A stool sample to look for parasites or infection is common, and some puppies need further tests.
4. Treatment. This may include a bland or gastrointestinal diet, probiotics, or medicine to treat parasites. Antibiotics are often not needed and are only used if a bacterial infection is suspected, because they can strip out healthy gut bacteria and make the dog's diarrhoea worse.
5. Hospital care. Very ill puppies, for example those with parvovirus or severe giardia, may need intensive care with intravenous fluids.

Take your puppy's vaccination card and details of any worming or flea treatments they have had. If you bought from a breeder, their paperwork should show what has been given and when.

Preventing diarrhoea in puppies

You can't prevent every upset tummy, but these habits remove the most common triggers.

• Change food gradually. The Royal Kennel Club suggests switching over about a week to ten days; Blue Cross says at least three days, starting with small amounts of the new food mixed into the old. Slower is kinder for a puppy.
• Keep diets consistent. Stick to one suitable puppy food and keep it the same from day to day.
• Worm on schedule. Keep worming up to date on the schedule your vet recommends.
• Complete the vaccination course. Vaccination is the main protection against parvovirus. Keep your puppy away from unvaccinated dogs and public areas until your vet says they are protected. Our guide to the puppy vaccination schedule explains the usual timings, but your vet's schedule always wins.
• Puppy-proof the house. Store cleaning products, medicines, pesticides, toxic plants and human food out of reach.
• No scraps or bones. Fatty human food and leftovers can lead to diarrhoea and pancreatitis, and bone fragments can irritate the bowel.
• Stop scavenging. Keep bins secure and keep your dog supervised in the garden and on walks.
• Keep a calm routine. A predictable day helps a new puppy settle, which reduces stress-related upsets.

New dog owners are often caught out by an upset tummy in the first week, so it helps to plan for it. When you are collecting your puppy, ask the breeder for a supply of the food your puppy is already eating and their vaccination and worming records, and register with a vet straight away. A responsible breeder will expect these questions, and our safe puppy buying checklist covers what else to ask before you commit.

Frequently asked questions

Will puppy diarrhoea go away on its own?

Mild cases often do. Diarrhoea from a food change or stress often settles within a few hours to a couple of days. If it lasts more than about 24 hours, or your puppy seems unwell at any point, call your vet.

Should I starve my puppy if they have diarrhoea?

No. Puppies need small, frequent meals and constant access to water, and starving a puppy with diarrhoea could be dangerous.

What can I give my puppy for diarrhoea?

Only what your vet recommends. That is usually water, rest and small meals of a bland diet such as boiled chicken and white rice, or a gastrointestinal diet from the vet. Don't use human medicines.

My puppy has diarrhoea but is acting normal. Should I worry?

A bright, playful puppy with one or two loose stools is less worrying, but still ring your vet for advice, especially if your puppy is very young or not fully vaccinated. Watch closely for symptoms like vomiting, lethargy, blood or loss of appetite.

Is diarrhoea with blood an emergency in puppies?

More than a small streak of blood, blood on more than one occasion, or black, tarry stools all need a vet straight away. Bloody diarrhoea can be a sign of parvovirus or a bacterial infection.

Is it normal for a puppy to have diarrhoea after vaccination or worming?

A mild upset can happen. After vaccination it should settle within about a day, and after worming within a few days. Call your vet if it is severe, lasts longer, or your puppy is weak, very tired or not eating or drinking.

Can a puppy have diarrhoea and vomiting at the same time?

Yes, and it is a dangerous combination because a puppy can dehydrate very quickly. Contact your vet straight away.