Bilious Vomiting Syndrome

Information about recurrent vomiting of yellow or green bile when a dog’s stomach has been empty for several hours.

What is bilious vomiting syndrome?

Bilious vomiting syndrome is a term used when an otherwise healthy dog repeatedly vomits bile, usually late at night or early in the morning after going for several hours without food.

Bile is a digestive fluid produced by the liver and stored in the gallbladder. It is normally released into the small intestine to help digest food. When the stomach is empty, bile and other digestive fluids may move back into the stomach and irritate its lining.

The vomit is usually a small amount of yellow or greenish fluid, mucus or foam. Some dogs appear nauseous beforehand and may lick their lips, swallow repeatedly, drool or eat grass.

Bilious vomiting syndrome is usually considered only when a dog is otherwise well and other causes of vomiting have been ruled out by a veterinary surgeon.

Typical signs

Vomiting late at night or early in the morning
Vomiting after the stomach has been empty for several hours
A small amount of yellow or greenish bile, mucus or foam
Lip licking, swallowing or drooling before vomiting
The dog appearing hungry and otherwise well afterwards
Normal appetite, energy levels and stools between episodes

Other causes must be considered

Yellow bile in vomit does not automatically mean that a dog has bilious vomiting syndrome. Vomiting may also be caused by dietary upset, parasites, pancreatitis, inflammatory bowel disease, liver or kidney disease, infection, food intolerance, toxins, medication or a foreign object in the digestive tract.

Repeated vomiting should therefore be discussed with your vet, particularly if it is a new problem or the dog has any other symptoms.

Contact your vet promptly if your dog:

Vomits repeatedly or cannot keep water down
Has blood in the vomit or vomit resembling coffee grounds
Has diarrhoea, particularly if it contains blood
Appears lethargic, weak, distressed or in pain
Has a swollen or painful abdomen
Is repeatedly retching without producing vomit
Loses weight or has a reduced appetite
Has pale gums or signs of dehydration
May have swallowed a foreign object or toxin
Is a puppy, elderly dog or has an existing medical condition

Feeding management

If your vet believes that your dog has bilious vomiting syndrome, they may recommend reducing the amount of time the stomach remains empty.

This may involve dividing the dog’s normal daily food allowance into several smaller meals rather than increasing the total amount of food given.

Some dogs improve when a small portion of their normal food is given shortly before bedtime, with another meal offered early in the morning.

Any additional bedtime meal should form part of the dog’s normal daily food allowance to avoid unwanted weight gain. Dietary changes should be introduced gradually and discussed with your vet if your dog has a medical condition or requires a prescribed diet.

Veterinary investigation

If changing the timing of meals does not help, or if the dog has other symptoms, your vet may recommend further investigation. This could include:

A physical examination and review of the dog’s history
Blood tests
Urine and faecal tests
Abdominal X-rays or ultrasound
Further digestive-system investigations if necessary

Keeping a diary can help your vet. Record when vomiting occurs, what the vomit looks like, meal times, changes in food, medication and any other symptoms.

Medication

If other causes have been ruled out and changing meal times is not enough, a vet may prescribe medication to reduce nausea, alter stomach acidity or help normal movement through the digestive tract.

Do not give human antacids, anti-sickness medicines or other medication unless your veterinary surgeon has confirmed the exact product and dose for your dog.

Outlook

Many dogs suspected of having bilious vomiting syndrome improve when their meals are divided and the overnight period without food is shortened.

If vomiting continues despite these changes, the diagnosis should be reviewed by a vet to ensure that another condition has not been overlooked.

Further information:

Blue Cross – Vomiting and diarrhoea in dogs

VCA Animal Hospitals – Vomiting in dogs

This information is provided for general guidance and is not a substitute for veterinary care. Repeated or unexplained vomiting should always be discussed with your veterinary surgeon.