Why does my puppy have diarrhoea?

It’s quite common for young dogs to have diarrhoea, but if your puppy is affected by it then it’s natural to worry about them and wonder what could have caused it. Puppies can get an upset tummy for many reasons, which makes it difficult to know when to look after them at home and when to contact your vet for advice. Find out everything you need to know about puppy diarrhoea and how to care for your dog when they’re unwell.

Why has my puppy got diarrhoea?

Puppy diarrhoea can be caused by stress, a new diet, viruses, bacterial infections, parasites, food intolerances, poisons, toxins or from eating things they shouldn’t. Understanding the likely cause can help you decide if you should manage their diarrhoea at home or contact your vet for advice.

What is diarrhoea?

Diarrhoea is the term that’s used when your dog’s poo is loose or watery. Having diarrhoea is often a sign that something isn’t quite right. Sometimes the cause might be minor and can be managed at home, but other times it might be more worrying and may need treatment from your vet.

What causes a puppy to have runny poop?

When food passes out of a puppy’s stomach, it travels through the small intestine as a liquid mix. Here, nutrients are extracted, and the digested food is then passed into the large intestine, where water is squeezed out of it and absorbed into the body, changing the solution into a more solid mass. If there’s a problem with the small or large intestine the puppy’s poo may come out as a liquid. These problems could be caused by viruses, bacteria, parasites or poisons.

How common is diarrhoea in puppies?

Diarrhoea is one of the most common reasons that puppies visit their vet. Puppies are sensitive to change, stress and infections, so most puppies have diarrhoea at some point in their early life. Most cases can be managed at home, but severe or prolonged diarrhoea can quickly make puppies very unwell.

How do I know if my puppy has diarrhoea?

There are different stages of diarrhoea, ranging from a soggy log shape to a liquid puddle of poo. Ideally, your dog’s poo should be solid and well-formed. The guide below shows you what your puppy’s poo should look like – ideally scoring a number two on the chart. Anything from four and above is considered diarrhoea.

Poo chart

What causes puppy diarrhoea?

There are a number of different triggers for diarrhoea in puppies. It’s not always easy to know why they’re unwell, but there are usually six main causes.


Being a puppy seems to be an exciting life, but it can be stressful too. Stress can trigger puppy diarrhoea, whether it’s moving to a new home away from their mum and siblings, meeting new dogs, going to the vet or visiting a new environment. As a puppy settles in and becomes used to their surroundings and routine, they should feel more comfortable and at ease, which should resolve any gastric issues relatively quickly. If your puppy’s diarrhoea persists, speak to your vet for advice.

Find out more about creating a good environment for your dog.

A change in diet

Puppies have very sensitive stomachs, and a sudden change in the food they eat can cause an upset stomach. If they have diarrhoea from switching foods too quickly then it should settle down in a few days. If possible, it’s much better to prevent this from happening by gradually introducing new diets. When you first get a puppy, it’s worth finding out about their diet and continuing to feed them the same one while they settle in. If you need to switch foods, add a small amount of the new food to what they currently eat. Give them a bit more of the new food each day while reducing the old food, slowly swapping one for the other. This should be done bit by bit over a week to ten days.

Find out more about feeding your puppy.

Food intolerances

Just like us, our dogs can develop a food allergy or food intolerance at any time in their life. However, it is actually very rare for them to develop one early in life. Any food ingredient could cause an allergy, but it’s almost always caused by a protein source – most commonly chicken, beef or dairy. If you suspect that the food that your dog eats is causing them to become unwell, talk to your vet.

Find out more about food allergies and food intolerances.

Bacterial and viral infections

A puppy’s immune system is not as strong as an adult’s, which means that they’re more at risk of becoming unwell. Puppies can become infected from eating contaminated food, drinking contaminated water or from other infected dogs, including the environment that they’ve been in and exposure to their poo.

Bacterial infections can include Salmonella, Listeria, E. coli or Clostridium.

Viral infections can include parvovirus, distemper, infectious viral hepatitis or types of coronaviruses (these are separate from COVID-19).

Many of these infections are very serious, can be fatal, and need to be treated by a vet. Viral infections may be a particular problem for puppies that haven’t been vaccinated yet, especially if their mother was not up to date on her vaccinations.


Young puppies can easily suffer from parasites that cause diarrhoea, such as roundworms, hookworms, tapeworms, whipworms, coccidia, and giardia - all of these require veterinary attention. Puppies tend to pick up parasites from their environment, infected poo or they can be passed from mother to puppy in the womb, so keep this in mind when visiting possible breeders that you’re thinking of buying a puppy from. If you’re buying a puppy and think that the environment is not clean, or the mother doesn’t look well then do not buy from this breeder.

If you suspect your puppy has worms, contact your vet for advice.

Find out more about worms.

Eating things they shouldn’t

Puppies love to investigate new things and tend to explore the world with their mouths. This means that they often eat things that they shouldn’t, whether that’s plants in the garden, rubbish from the bin, medicines that have been left on low surfaces, other pet’s poo or cleaning products in cupboards. Some of these things can be toxic to dogs and you should contact your vet if your dog eats something that they shouldn’t have. Fatty foods can make dogs ill and many human foods can be toxic to dogs, including chocolate, onions, some artificial sweeteners, grapes, raisins and sultanas.

Find out more about things that can be poisonous to dogs.

What to do if my puppy has diarrhoea

If your puppy has diarrhoea, read our guide below to see if they need to visit the vet. When in doubt, always speak to your vet for advice.

Puppies with diarrhoea can become dehydrated quickly. Make sure they have access to water and try to encourage them to drink. If they’re not keen on drinking, try pouring a little bit of the juice from a can of tuna (making sure to avoid tuna in brine as this is salty and could make them more dehydrated) into their water or give them ice cubes to lick or chew on (read our hints and tips on giving ice to a dog). If they’re not drinking, then contact your vet.

When you’re clearing up your puppy’s diarrhoea, look to see whether there’s any blood, mucus or parasites. If you contact the vet, ask if you should bring along a sample of your dog’s poo. If you do need to, make sure to put it in a plastic bag or container and double-bag it. If you’re not seeing the vet for several hours, you could put the double-bagged sample in the fridge. When you’re cleaning up your puppy’s diarrhoea, make sure you use a pet-friendly disinfectant to kill off any nasty bugs.

When should a puppy with diarrhoea visit the vet?

If your puppy has diarrhoea, it can be tricky to know whether or not it calls for a visit to the vet. There are a number of different signs to watch out for, but you should contact your vet if:

  • The diarrhoea is severe
  • The diarrhoea is frequent (several bouts over a few hours), especially if it’s very liquidy
  • The diarrhoea lasts longer than a day
  • They’re not eating or drinking
  • Your puppy is getting worse
  • Your puppy is very young or very small
  • Your puppy has any other health conditions, such as kidney problems etc.
  • You see blood in their diarrhoea, especially if it’s more than a single small streak or if it’s on more than one occasion
  • You see worms in their poo or in their sick
  • Their poo is black and tarry; this could be a sign of digested blood
  • Their diarrhoea has a very strong or unpleasant smell
  • They are vomiting, especially if there’s blood in their sick
  • Your dog is regularly straining to poo, but nothing is coming out
  • Their gums are pale, blue or are tacky to the touch (this could suggest they’re dehydrated)
  • Their tummy is painful to the touch or is bloated
  • They show other concerning signs like weakness, they feel hot or they’re very tired
  • You think your dog has eaten something unusual, potentially toxic or something that could cause a blockage in their stomach or intestines

If your puppy doesn’t have any of these signs but you’re still concerned about them, then if in doubt always contact your vet.

How to treat diarrhoea in puppies at home

If you don’t need to take your puppy to the vet, make sure that your dog has access to fresh water to keep them well hydrated. If they’re reluctant to drink, try dribbling a little bit of the liquid from a can of tuna into their water (making sure to avoid tuna in brine as this is quite salty and could make them more dehydrated) or give them ice to lick or chew on. If they are drinking, try feeding them a bland diet for a few days. This could take the form of boiled chicken breast and cooked white rice. Alternatively, you could feed them a commercial gastrointestinal diet (such as Purina PRO PLAN® Veterinary Diets EN Gastrointestinal) – these are preferable to chicken and rice as they have a specific feeding guide to ensure you meet your puppy’s energy needs and have a number of specific ingredients within them specifically designed to really help support your puppy’s tummy as much as possible. Probiotics that are intended for dogs could also be helpful, such as PRO PLAN® Fortiflora. If your dog is not drinking, gets worse or continues to have an upset stomach then talk to your vet for advice.

What to feed a puppy with diarrhoea?

It might take a little while for your puppy’s diarrhoea to settle down, so in the meantime make sure not to feed them anything that’s going to further upset their delicate stomach. If your puppy’s diarrhoea is mild, keep them on a bland diet until they stop having an upset stomach and then gradually switch back to their usual food.

You should begin by feeding them small portions of plain boiled white rice mixed with boiled chicken (with the skin and bones removed). Alternatively, and ideally, as mentioned above, you could feed them a specific gastrointestinal diet as this will maximise support to your puppy’s gut. This diet should help settle their stomach and within a day you should see your puppy’s poo turn back to its normal consistency. It’s important to remember that if your puppy’s condition doesn’t return to normal or seems to worsen, you should contact your vet as soon as possible.

How often should I feed a puppy with diarrhoea?

After your puppy has had diarrhoea, it’s important to feed them an appropriate diet little and often throughout the day (for example, 6-8 small meals). Hopefully, this will allow their digestive tract to begin to process food properly again. Make sure they also have access to fresh water to keep them hydrated. If your puppy continues to be unwell, speak to your vet for advice. Once your puppy is going to the toilet normally, gradually reintroduce their usual food over a few days.

Should I starve a puppy with diarrhoea?

No – it could be dangerous if you try to starve a young puppy, especially if they are already unwell. Starving a dog of any age when they have diarrhoea is not recommended: the intestines need food within them to repair and recover. However, it is even more important that your puppy is being fed little and often when they are very young, and that they have access to water, as dehydration can be dangerous.

Does diarrhoea in puppies go away on its own?

Puppy diarrhoea may only last a few hours, or it can go on for a couple of days; it all depends on what’s causing it and how healthy the puppy is. Always talk to your vet if your puppy has diarrhoea for more than a day.

How to prevent puppy diarrhoea

Puppy diarrhoea is surprisingly common, so no matter what you do it may be impossible to completely prevent it. There are several things you can do to try to stop it from happening in the future, these include:

  • When introducing a new diet, make sure you do it gradually, especially if you’re moving away from the food that your breeder used to feed them, or are moving from puppy to adult food
  • Keep your house clean, especially if you have other pets. Make sure to use a pet-friendly disinfectant
  • Make sure your puppy is vaccinated and wormed at a suitable age (your vet will be able to recommend when they should have these treatments, and to recommend effective products)
  • Until your puppy is fully vaccinated, keep them away from unvaccinated dogs or public places that unvaccinated dogs may have been, such as parks
  • Poison-proof your home by putting cleaning products, pesticides and medications high up or in cupboards that your puppy isn’t able to get into. Keep any houseplant out of paws reach and make sure they can’t reach any human foods that might be dangerous to them
  • Don’t feed your puppy any salty or fatty foods and ideally avoid feeding any table scraps
  • Pick up your dog’s poo as soon as possible
  • Try to reduce stress where possible. Getting your puppy into a good routine can help with this
  • Keep a close eye on your puppy to make sure that they’re not eating anything they shouldn’t be
  • Feed your puppy a well-balanced diet and ensure they’re getting adequate exercise and play
  • Make sure your puppy attends all recommended trips to the vet to ensure that your vet is checking on their health

Why does my puppy have diarrhoea with mucus?

Mucus is the jelly-like substance you might occasionally see in your dogs’ poo. It’s normal for dog poo to have a small amount of mucus in it, but large amounts can be a sign that something isn't quite right. Your dog produces mucus in their large intestine to help poo slide through the colon easily. This naturally passes out of them when they go to the toilet. Larger amounts of mucus in your dog’s poo can be a sign of inflammation or irritation in their gut and could be caused by a number of things, such as parasites, stress, infection, changes in diet, food intolerances or poisons. Red mucus could be a sign of bleeding. This might not be an emergency, but you should contact your vet for advice.

My puppy has diarrhoea with blood in it – what does it mean?

Blood in your puppy’s diarrhoea could be a sign of inflammation in their intestines or could be caused by a burst blood vessel from straining too much when going to the toilet. A small amount on just one occasion may not be overly concerning, but if there’s a lot of blood, or if it continues to happen, you should speak to your vet. These signs could suggest parasites, infection or a number of other issues. 

My puppy has vomiting and diarrhoea, what should I do?

It’s quite easy for a puppy to become dehydrated, so if your puppy has both vomiting and diarrhoea, then it can be a dangerous mix. Dehydration can occur quite quickly, so it’s important that you try to encourage your puppy to drink, but you should also contact your vet for advice, especially for very young puppies.

Is it normal for puppies to have diarrhoea a lot?

Most puppies experience diarrhoea at some point in their early life, but if your puppy is regularly having an upset stomach then you should speak to your vet to see if you can both get to the bottom of things. It’s important that you and your vet try to find out what’s causing your puppy to become unwell.

For puppies that experience regular diarrhoea, a specially formulated diet can help, for example PRO PLAN® Puppy Sensitive Digestion. These sorts of diets often have a combination of nutrients that support the digestive system.

Can my puppies teething give them diarrhoea?

Some owners say that their puppy gets diarrhoea when they're teething. This could be because their sore gums are making them feel stressed and uncomfortable, which in turn can cause diarrhoea. It could also be caused by them chewing on things to relieve the pain and may be chewing on things that could be irritating their stomach or giving them mild infections. Whatever the cause, if your puppy has severe diarrhoea, or if it’s prolonged or accompanied by other concerning effects, speak to your vet for advice.

Can a puppy have diarrhoea after worming?

After being given deworming treatment, some dogs may seem a little tired or may have diarrhoea. This is especially true if your dog has been affected by worms. These effects should only last a few days, but if they do go on for longer, or your puppy is very tired, weak or is not eating or drinking, call your vet for advice.

Why does my puppy have diarrhoea after their vaccination?

Some puppies may have mild diarrhoea after being vaccinated. This could be a small adverse reaction to their injections, or it could be caused by the stress of visiting the vet. Either way, it should settle down in a day or so. Serious side effects from vaccinations are very rare but contact your vet if your puppy’s diarrhoea is more severe, continues for more than a day, gets worse or if they develop other signs, such as vomiting, breathing problems or itchy/bumpy skin.

Why does my puppy have diarrhoea after antibiotics?

Your puppy’s gut is full of good bacteria that help to break down food and protect against invasions of bad bacteria. Antibiotics kill off both the good and bad bacteria, causing an imbalance that can result in diarrhoea. Your puppy should stop having diarrhoea once they’ve stopped their course of antibiotics but talk to your vet and ask if there’s anything you can do to help your dog in the meantime, such as a gastrointestinal diet or probiotics.

My puppy has diarrhoea – could it be parvo?

Parvovirus is a highly contagious and potentially deadly virus in dogs. It can cause diarrhoea, but is usually accompanied by other signs, such as vomiting, lethargy or a high temperature. Parvovirus is a very serious condition, especially in puppies, and the earlier it’s treated the better the outcome. If you think your puppy may have parvovirus, then speak to your vet at once.

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