According to VCA Animal Hospital, gastroenteritis is a condition in which dogs vomit foamy yellow bile. Gastroenteritis is an inflammation of the large intestine, small intestine and stomach. Gastroenteritis in dogs is caused by viruses, parasites or bacteria. Additional symptoms include abdominal pain and diarrhea.
Leo's Pet Care Veterinary Clinic explains that dogs possess a physical defense mechanism that causes them to vomit repeatedly until the stomach is empty. It is common for dogs to throw up foam and yellow bile once they have emptied out the contents of their stomachs. If a dog continues to vomit over a 12 hour period, it is important to consult with a veterinarian as this is a common sign of an obstruction caused by a foreign object.
According to PetMD, occasional vomiting in dogs is normal, but chronic vomiting can signify an underlying condition. It is important for dog owners to consult with a veterinarian as soon as possible if the vomit is tinged with dark blood or their dogs are vomiting non-stop. Causes of acute vomiting include eating too fast, food intolerance, allergic reactions, heat stroke, parasites, stomach ulcerations and metabolic disorders. Foamy bile vomit often indicates inflammatory bowel disease or an inflamed pancreas.