Vomiting is a complex reflex in which the stomach contents are forcibly expelled through the mouth. Vomiting in ferrets is usually preceded by symptoms of nausea such as salivating excessively, pawing at the mouth, licking the lips and walking backwards. Vomiting can be triggered by irritation of the lining of the stomach or intestinal tract because of inflammation, infection or foreign bodies.

Vomiting receptors are located in nerves supplying the intestinal tract and in the central nervous system. Irritation of these receptors by chemical mediators like toxins or drugs will also trigger vomiting. Disorders that affect your ferret's balance center (vestibular system) located in the brainstem and inner ear, such as motion sickness or inner ear infections, may trigger violent episodes of vomiting.

Vomiting is seen less frequently in ferrets with gastrointestinal disease as compared to other pet mammals. Many conditions, such as gastric ulcers or foreign bodies, readily cause vomiting in dogs and cats. Ferrets with these conditions usually show other symptoms, such as decreased appetite and weight loss, and will only occasionally vomit.

The appearance of the vomitus can be helpful in discovering which disease process is causing the vomiting. Foreign objects, tumors or other masses in the stomach often obstruct the opening from the stomach to the intestines. This prevents food from emptying from the stomach and often causes vomiting. In these cases, the vomitus will appear as undigested or partially digested food. Food that is liquid in consistency, digested and stained with bile suggests vomiting caused by diseases of the intestinal tract, toxins or metabolic diseases. Fresh blood in the vomitus, or digested blood that has the appearance of coffee grounds is seen with ulceration of the lining of the stomach or intestines.

Causes

There are many causes of vomiting in ferrets. The cause may be very simple, such as a dietary change, or may be due to a number of complex disease processes. There are many contagious diseases that cause diarrhea, so it is important to inform your veterinarian of any potential contact – direct or indirect – with other ferrets. Possible causes of vomiting in ferrets include:

Bacterial infection. Bacterial infections are among the most common causes of vomiting in ferrets and may infect the stomach, small intestine or large intestine. Helicobacter mustelae is an extremely common cause of stomach ulcers, causing melena (digested blood in the feces) and sometimes vomiting. Campylobacter spp., Salmonella sp., Clostridium spp, and Desulfovibiro are other common bacteria that cause disease in the intestines.

Obstruction. Tumors or foreign objects may block the intestinal tract. Ferrets are extremely fond of chewing, and will often swallow toys. Most ferrets with intestinal obstruction will have vague symptoms such as weight loss, lack of appetite and diarrhea. Occasionally, an intestinal intussusception (telescoping of one part of the intestinal tract into another) may cause diarrhea initially, then a lack of feces later in the course of disease.

Viral infection. Epizootic Catarrhal Enteritis (ECE) is commonly known as "green slime disease" because of the characteristic green, mucous covered diarrhea produced by affected ferrets. Vomiting occurs alone or in combination with diarrhea in ferrets with ECE. The specific virus causing this disease has not yet been isolated. The disease appears to be highly contagious, and is usually spread by young ferrets that shed the virus without showing any symptoms (asymptomatic carriers). Other, less common causes of vomiting include rotavirus and parvovirus (Aleutian disease virus, not canine parvovirus).

Parasitic causes. Intestinal worms are rare. However, microscopic parasites, such as Giardia, coccidia, and Cryptosporidium may cause vomiting in ferrets. These parasites are more likely to contribute to diarrhea when a bacterial or viral infection is also present.

Neoplasia. Cancer, especially lymphoma, is extremely common in ferrets of all ages. Lymphoma may cause vomiting by invading the intestinal tract or liver. Primary cancers of the gastrointestinal tract, such as adenocarcinoma, are less common neoplastic causes of vomiting.

Metabolic disorders. Liver disease, renal disease, pancreatic disease may all cause vomiting.

Infiltrative Disease. Eosinophilic gastroenteritis is a condition in which a eosinophils (a type of white blood cell whose normal function is to fight infection) invades the intestinal tract. The cause of this disorder is unknown. Proliferative bowel disease is a condition in which lymphocytes and plasmacytes invade the large intestine. This disease is cause by a bacteria (Desulfovibiro).

Drugs and toxins. These include plant toxins, heavy metal toxicity, bacterial toxins from spoiled food.

Vaccine reaction. Ferrets often begin vomiting within one hour following administration of vaccines when an allergic reaction occurs. These ferrets should be taken to the veterinarian immediately.

Dietary. These include diet changes, eating spoiled food and dietary intolerance.

Vestibular disease. This includes motion sickness or diseases of the inner ear.

Stress induced. This would include sudden change in environment.