Vomiting and diarrhoea

Vomiting and diarrhoea are very common in dogs. Both are symptoms of other conditions rather than diseases in their own right and there is a vast range of dog diseases in which diarrhoea and/or vomiting may occur. In many cases the problem may be successfully treated without ever pinpointing the actual cause. However, the information that you give your vet may be vital in deciding whether the case is serious enough to need further detailed investigations.

Diarrhoea occurs when the normal functioning of the large bowel (intestine) is disturbed. The large bowel is responsible for absorbing water from the gut and if it does not do this properly, very liquid faeces (droppings) are produced.

Vomiting occurs when stomach juices are expelled from the mouth. It is important to distinguish vomiting from regurgitation. Regurgitation only occurs after a meal and the material will have visible lumps of undigested food which are often eaten again.

The causes of both diarrhoea and vomiting include viral, bacterial or parasitic infections; changes in diet, stress or excitement, poisonous drugs or chemicals, blockages or damage to the digestive system or other body organs.

Dogs will eat anything and vomit readily as a protective mechanism to prevent toxic substances entering the body. Vomiting involves big contractions of the abdominal muscles before the stomach contents are eliminated, and your dog may salivate excessively or swallow immediately prior to doing so.

If your dog has diarrhoea it may need to go to the toilet more frequently or have accidents in the house. Occasionally, bowel movements are not more frequent but just softer than normal.

Both diarrhoea and vomiting occur as short lived (acute) conditions lasting 1-2 days which will often clear up on their own, and as long-term (chronic) problems which are usually more serious. If your dog does not appear to be in distress or be losing weight, all you may need to do is to withhold all food for a day and then give your dog small amounts of cooked fish, chicken or some other food which is easily digested. Make sure clean fresh water is available.

If vomiting or diarrhoea is continuous for more than 24 hours (despite fasting), your dog could become dangerously dehydrated and should be taken to your vet.

Contact your vet sooner for puppies (they dehydrate more quickly than adults), if there is blood in the vomit/diarrhoea or if the faeces are of a black and tarry appearance (an indication of internal bleeding).

Never treat your dog yourself with drugs from your own medicine cabinet because some human drugs may be poisonous to dogs.

Diarrhoea or vomiting will be managed by fasting (unless your dog is dehydrated, in which case it may be given fluids and essential minerals by mouth or injection). Your vet may not give antibiotics because bacterial infections are one of the rarer causes of these problems and because ‘good’ bacteria are always present in a normal gut. Therefore, antibiotics (which also kill these bacteria) could actually make the problem worse.

Your vet will ask you questions about your dog, such as:

  • Is your dog ill or depressed?
  • Has your dog eaten any unusual foods?
  • Is there anything unusual about the colour and smell of the your dog’s faeces or vomit?
  • When and how often is your dog being sick or having diarrhoea?
  • Are there other dogs in the household and have these also been affected?
  • Has your dog been hunting or scavenging left over human food?
  • Has your dog been given any medical treatment or been exposed to any potential poisons?
  • Think about these questions before going to your vet and see if you can identify any possible reason why your dog may be ill.

If the illness continues for more than a couple of days it may be necessary for your vet to carry out a range of tests to find out the cause of the problem. A small sample of your dog’s faeces will be examined for bacterial infections or parasites in the gut. Blood tests may also be taken to check for infection, kidney or liver disorders.

An x-ray may be needed to see if there is anything abnormal in the gut. Sometimes your vet will put an endoscope into your dog’s stomach and intestine to try and see the cause of the problem, and a small biopsy sample of intestine may be removed for examination.

Digestive upsets are unpleasant for you and your dog but in most cases your dog will be better within 1-2 days. If your dog is not improving after 24 hours make an appointment with your vet for further advice.