Dog Diarrhoea: What to Do and When to Worry

Call your vet now if

• There is blood in the stool, whether bright red streaks or a lot of it, or the stool looks black and tarry.
• Your dog has repeated diarrhoea together with vomiting.
• They seem lethargic, weak, or not themselves.
• They are a puppy, especially one who is not fully vaccinated. Puppies can become poorly quickly, and some serious infections cause diarrhoea.
• You notice signs of dehydration: sunken eyes, dry or tacky gums, reduced energy, or skin that is slow to settle back when gently lifted at the scruff.
• You think they may have eaten something poisonous (check our toxic foods list) or swallowed an object.
• Their belly seems painful or swollen, or they are straining without producing much.
• They are elderly, very small, or have an existing health condition.

You do not need to wait and see if any of these apply. Ring your vet, or an out-of-hours emergency vet if your practice is closed.

What counts as diarrhoea

Diarrhoea means stools that are looser, more frequent, or more urgent than usual for your dog. It can range from soft, unformed stools to watery liquid. Every dog has their own normal, so it helps to know what yours usually looks like.

Some things worth noticing:

• Consistency. Soft, cow-pat, or watery.
• Frequency. How many times in a day, and whether they are asking to go out urgently or having accidents indoors.
• Colour. Usual brown, yellow, grey, green, red, or black.
• Other features. Mucus (a jelly-like coating), blood, undigested food, or anything unusual such as fabric or plastic.

Straining can be confusing. A dog with diarrhoea may strain because their gut feels irritated, but straining can also be a sign of constipation or a urinary problem. If you are not sure what you are seeing, tell your vet.

Common possible causes

Diarrhoea has a wide range of possible causes. Some everyday possibilities include:

• Scavenging. Bins, rotting food, or something found on a walk.
• A sudden change of diet. Switching food quickly, or a rich treat or table scraps.
• Stress or excitement. Kennels, travel, visitors, or fireworks can upset some dogs' tummies.
• Parasites. Worms and other gut parasites, especially in young dogs. Our guide to fleas, ticks and worms covers routine prevention.
• Infections. Some viral and bacterial infections affect the gut.

Diarrhoea can also be linked with food intolerances, inflammatory gut conditions, and problems elsewhere in the body, such as the liver, kidneys or pancreas. These are possibilities only. Your vet is the right person to work out what is behind it in your dog.

Safe steps while you watch

If your dog has had a short bout of diarrhoea but is bright, drinking and behaving normally, these steps can help:

• Keep fresh water available at all times. Diarrhoea causes fluid loss, so drinking matters. Check the bowl often and refill it.
• Note the frequency and appearance. Jot down when each episode happens and what it looks like. A photo can be surprisingly useful to your vet.
• Avoid human anti-diarrhoea medicines. Some products made for people are unsafe for dogs, and others can hide important signs. Only give what your vet has prescribed for your dog.
• Ask your vet about food. Your vet may suggest a bland diet or a specific gut-friendly food for a short time. Check with them rather than guessing, especially for puppies, small breeds, and dogs with conditions such as diabetes. Please ask before withholding food.
• Offer more toilet breaks. Let them out more often so they are not left uncomfortable, and be patient with accidents.
• Keep them clean. Gently clean around the bottom if needed, and wash bedding.
• Wash your hands. Some causes of diarrhoea can spread, so good hygiene protects you and other pets.

Keep checking on their energy and gums. If anything changes, or the diarrhoea is not improving, ring your vet.

When to book an appointment

Even if your dog seems well in themselves, some patterns are worth a vet visit:

• Diarrhoea that lasts more than a day or two, or keeps coming back.
• Weight loss or a change in appetite (see my dog won't eat).
• Regular mucus in the stools.
• Drinking more than usual.
• Diarrhoea alongside on-and-off vomiting (see dog vomiting: when to see a vet).

Your vet may want to examine your dog, and may ask for a stool sample. If they do, collect a fresh one in a clean bag or pot and keep it cool.

Building a clear picture

Your vet will usually ask how long it has been going on, how often, and whether anything else has changed. Logging stools, meals and energy in Petopedia helps you give your vet a clear picture rather than relying on memory. You can sign up to start a log, and our guide to knowing your pet's normal explains which everyday details are worth recording.

For a broader checklist of warning signs, read signs your pet needs a vet.