Sickness and Diarrhoea


Sickness (vomiting) and diarrhoea is very common in our pets, especially in dogs. There are many reasons that your pet may exhibit vomiting or diarrhoea.  We have outlined many of the common causes below, but it is important to always contact your vet if you are worried, as not every case is the same.




Dietary indiscretion – this means your pet has eaten something they shouldn’t have, and is most common in dogs that scavenge things whilst out on walks or root through bins!

Infection – most commonly viral infections passed on from other animals but there are a few specific bacterial infections such as Campylobacter. Campylobacter bacteria can infect many species of animals and are present in faeces from infected individuals. This is usually where your pet will pick it up when they are out and about. It is important to be aware that humans can also be infected with Campylobacter:  you should always practice good hygiene around your pet, and be careful if you have young children who may be more susceptible to infection. Click here to visit our hygiene at home page


Obstruction – this occurs when something is eaten that gets stuck part way along the digestive tract (stomach and intestines). Examples include toys, socks, bones and in cats long pieces of thread.

Food intolerance – some animals may have an intolerance to certain food types, for example a particular meat, gluten or rice.

Pancreatitis – this means inflammation of the pancreas. The pancreas secretes the enzymes needed to digest food in the intestine. This condition can vary in severity. It is usually painful and causes sickness and reduced appetite.

Inflammatory disease.

Tumours of the stomach or intestines.




Your vet will ask you some questions about your pet’s condition to try to identify a likely cause. These may include whether they are bright and alert or dull and depressed, if they are off their food, how often they are sick/having diarrhoea and what the diarrhoea is like. They will examine your pet including taking their temperature and feeling their tummy, as well as getting an idea of whether they are dehydrated. Often if your pet is well in themselves your vet may try treating the problem symptomatically especially if it is just diarrhoea, but otherwise they may wish to do further investigations such as:


Sending away a faecal sample to check for worms, protozoa (single cell organisms such as Giardia) and bacteria.

Carrying out blood tests to check other organs such as the pancreas, liver and kidneys, assess whether your pet is dehydrated, and look for signs of infection. Click here to visit our blood sampling page

Taking x-rays of your pet’s abdomen (tummy) or performing an ultrasound scan to look at the stomach and intestines as well as other organs. Click here to find out more about x-rays and diagnostic imaging

Performing endoscopy – this involves passing a very small camera through the mouth and down into the stomach to look at the lining and its contents.




For mild cases of sickness and diarrhoea, or just diarrhoea, where dietary indiscretion or a viral infection is suspected the symptoms will often pass with time. There is usually no need for antibiotics in these cases, and sometimes antibiotics can upset the natural balance of commensal bacteria in the intestine and make things worse. Commensal bacteria are the normal healthy bacteria that help your digestive system to function as it should. Your vet may suggest a probiotic which contains these commensal bacteria to help rebalance the population in your pet’s digestive system. They may also suggest feeding a bland diet for a few days, such as a prescription food for sensitive tummies.

If the symptoms do not improve further investigation may be necessary.  You should always let your vet know if your pet is not better after treatment.

If a faecal sample has been sent away and bacteria have been isolated then appropriate antibiotic treatment may be necessary.

If your pet is unwell or dehydrated they may need further treatment such as intravenous fluids (going on a drip) while further tests are carried out.

If any of the other conditions listed above are suspected or diagnosed your vet will be able to advise you about further treatment.




Disclaimer:  This website has been designed to offer information surrounding the use of antibiotics and infection control for pet owners.  It does not replace advice from your veterinary surgeon.  If you believe your pet is unwell or you have any questions relating to their treatment, please always contact your veterinary surgeon for advice.