Affected Animals:
Dogs and cats.

Overview: Vomiting is one of the more common reasons why owners take their dogs to the veterinarian.  Isolated episodes of vomiting rarely are a cause for concern as long as the dog has an appetite and is bright and alert; most healthy dogs will, on occasion, vomit whole or partially digested food, grass, or foamy, clear liquid.

However, excessive or chronic vomiting lasting for several days can indicate a more serious underlying condition that requires treatment. Dogs that vomit for more than a day, or seem depressed and are not eating should receive prompt veterinary attention so that the cause of the vomiting can be determined and dehydration can be treated.

Clinical Signs:
Nausea will sometimes cause dogs to salivate.  They may vomit food, clear liquid, stained yellow bile, grass or blood. Depending on the underlying cause of the vomiting, the dog can have a good or poor appetite, diarrhea, dehydration, or other signs.  There can be weight loss if the disease has been going on for a while and the gums may be tacky or dry from dehydration. 

Symptoms:
Owners frequently indicate that their dog has been salivating and vomiting whole undigested or digested food and a foamy fluid that may be yellow from bile, clear, or have blood in it.  Some people report that their pet eats grass and then vomits the grass.   Some dogs may maintain a good appetite, while other lose theirs entirely.  There can be weight loss if the disease has been going on for a while and the gums may be tacky or dry from dehydration. 

Description: Vomiting is a reflex action in which food and/or fluid are brought up from the stomach through the mouth. Vomiting occurs when the vomiting center of the brain called the chemoreceptor trigger zone, located in the medulla, is stimulated by specific nerve impulses from the body.   Diseases and certain situations such as a car ride can stimulate the nerves leading to the vomiting center, resulting in nausea and vomiting.   Many anti-vomiting medications actually work by blocking the signals from reaching the chemoreceptor trigger zone.

Complications of vomiting may include dehydration, weight loss, and aspiration pneumonia, which occurs when vomitus is inhaled into the lungs causing pneumonia.

Diagnosis: The examining veterinarian will need to get a thorough history from the owner and perform a complete physical exam on the animal to determine the severity of the vomiting and how long it has been occurring.  Some dogs do not actually vomit; instead they regurgitate.  This means the food quickly comes back up the esophagus soon after eating.  Thus, food will be undigested and it often may resemble a tube in shape.  When dogs have these symptoms, the veterinarian will assess that the disease may be in the esophagus, rather than in the stomach or intestines.

If the vomiting has been occurring for any length of time, baseline laboratory work is needed to help determine if there is any disease affecting the organs such as the liver, kidneys, and pancreas. A fecal flotation examination often is done to detect the presence of intestinal parasites which can cause vomiting. X-rays often are needed to detect problems in the abdomen such as a foreign body in the stomach or intestine, which can occur when a dog swallows something such as a ball or a small toy. 

Sometimes a barium contrast study is needed. Barium liquid outlines the gastrointestinal tract on the x-ray film and helps determine if there are any abnormalities. Other diagnostic tools include ultrasound, which uses high frequency sound waves to outline the details of the abdomen.  Endoscopy involves placing a tiny camera down the mouth and into the stomach and intestines to look for disease.  Tissue samples often are taken and sent to a laboratory to determine if the tissues are normal.  In other cases, exploratory surgery is required to diagnose the problem.  Referral to a veterinary internal medicine specialist for further diagnostics and treatment may be necessary in some cases.

Prognosis:
Animals that only vomit for a day or two, but are not sick and do not have an underlying disease usually have an excellent prognosis.  For animals that have been vomiting for several days, the prognosis is dependent on the cause and how quickly the owner seeks veterinary attention.  Rapid medical attention usually offers the best prognosis because the underlying disease will have less time to cause damage.   

Transmission or Cause:
There are numerous causes of vomiting. Some examples include motion sickness, drugs, and gastrointestinal tract obstruction which can occur when a dog swallows a foreign object like a golf ball. Inflammation of the gastrointestinal tract due to inflammatory bowel disease, parvovirus, and parasites frequently produces vomiting. Diseases of the kidneys, liver, pancreas,  and other vital organs, and even overeating may cause vomiting as well.

Treatment: For dogs that have been vomiting only a short time, but have an appetite and are bright and alert, symptomatic treatment for one to three days is usually very effective.  Typically in mild cases, food is withheld for 24 to 36 hours and injections of medications can be given to help alleviate the vomiting.  Owners should never withhold water unless instructed to do so by the examining veterinarian.  If the vomiting persists, or the animal is visibly sick, the use of intravenous fluid therapy will correct and prevent further dehydration.  Drugs also can be given intravenously instead of orally.

Further treatment is based on finding and correcting the underlying cause of the vomiting.   Different conditions require specific treatments.  A dog that swallowed a golf ball for example, needs to have the ball removed surgically in order to stop the vomiting.  A dog with parvovirus needs anti-vomiting medications, antibiotics, antacids, and supportive care until the virus runs its course.  The examining veterinarian will determine the best treatment needed for the animal.

Prevention:
In many cases owners can prevent vomiting, often through common sense and precautionary measures. Owners should take steps to secure all drugs and household poisons, strings and small toys that can be swallowed, as well as trash and garbage. Dogs should be fed a consistent diet, without overfeeding. Bones, human snacks, and table foods are generally discouraged.