Vomiting and diarrhoea in dogs

Similar to humans, there are a number of reasons why dogs vomit. Causes can include:

• eating something that doesn't agree with them
• overeating
• a food allergy
• bacterial or viral infections of the gut
• consumption of something toxic
• an obstruction
• gastrointestinal worms
• car or motion sickness
• heatstroke
• parvovirus
• liver, kidney or pancreatic problems

If your dog has been sick, but has no other symptoms and is behaving normally, there is usually no cause for concern. The following steps can help your dog to feel better:

• If your pet is vomiting and unable to keep food down, you can try missing one meal, although still allow access to water. Then offer small amounts of a bland diet. If there is no further vomiting, feed small amounts every two hours and then gradually mix in their usual food over 24 hours before giving them a normal meal.
• Do not let your dog drink too much water at once as this can result in further vomiting. Give cooled, boiled water little and often.
• Dogs are said to eat grass when they are feeling nauseous to make themselves sick and improve digestion. But more often than not they do this for no other reason than it tastes good.

Important: If your dog has been vomiting for more than two days, speak to your vet. You should also contact your vet if your dog is refusing to eat, or is lethargic or depressed.

Most commonly, diarrhoea in dogs is caused by scavenging behaviour and eating something they shouldn’t or a change in diet. 

Other less common causes include:

• stress
• bacterial, viral or parasitic infections of the gut
• dehydration
• a disease affecting the bowel
• bones and bone fragments
• eating something poisonous 
• heatstroke
• problems with the liver or pancreas

If your dog has diarrhoea but is not behaving unusually and has vomited no more than once, there is usually no cause for concern. The following steps can help your dog to feel better:

• Offer small amounts of a bland diet. If there is no further diarrhoea, feed small amounts every two hours and then gradually mix in their usual food over 24 hours before giving them a normal meal. Continue to monitor their poo.
• Encourage your dog to drink, diluting some chicken stock in water to encourage this if needed. But if your dog’s diarrhoea is accompanied by vomiting, do not let them drink too much at once as this may make them sick again. Instead, give cooled, boiled water little and often.

Important: Elderly or very young dogs, or dogs with underlying health conditions are more at risk of health complications. Puppies can quickly become dehydrated because of diarrhoea. You should seek urgent vet advice if your dog is lethargic, repeatedly vomiting, drinking or urinating more often, having seizures, or has blood in their poo.

Not all causes of diarrhoea or vomiting can be prevented. But ensuring that your dog sticks to the right diet (free of any human food or leftovers) will keep their stomach in the best health. You can also follow these steps to prevent health problems:

• Make sure you keep any toxic substances such as chocolate or chewing gum (containing xylitol) well out of reach
• Ensure that your garden does not contain any poisonous plants
• Keep your dog's worming treatment up to date
• Try to prevent your dog from scavenging by keeping your rubbish secure. If necessary, you can also use a muzzle when walking your dog in the park.
• Never give your dog bones. Bowel irritation from chewed up bone fragments can cause gastrointestinal upsets and blockages.
• Switching foods can also cause stomach upsets in dogs, so it’s best to make diet changes gradually. Take at least three days and start by adding small amounts of the new diet to the current one.

If your dog appears otherwise healthy and is eating, then consider whether your dog could be coughing – kennel cough is common. 

If your dog seems uncomfortable, dull and is drooling constantly, contact your vet immediately. This could be a sign of bloat or something being stuck in the oesophagus (windpipe), both of which are emergencies.

Like humans, dogs will vomit bile which looks like yellowy green foam, when their stomach is empty. The substance is produced by the liver and stored in the gallbladder. Some dogs vomit bile regularly for no apparent reason and it is rarely a cause for concern. But contact your vet if this becomes excessive.