While the terms vomiting and regurgitation are often used interchangeably, they describe very different actions. Knowing the difference can help to diagnose the cause and identify the best treatment.
When your pet ‘throws up’ he may be either vomiting or regurgitating. Vomiting is often described as an active process, with a variety of signs it is about to occur. In contrast, regurgitation is passive and may occur without any warning. While vomiting may be initiated by diet, toxins, or inflammation, regurgitation is usually related to diseases of the esophagus. Using the correct term when speaking with your veterinarian helps him or her to focus more quickly on the most likely cause of the problem.
Vomiting is usually preceded by signs of discomfort – contraction of abdominal walls, salivation, licking lips and finally heaving, followed by emptying of the stomach contents or even contents of the upper small intestine. The vomit may be yellow or orangish in color, indicating the presence of bile. However, bile is not always present. A pet may vomit either food, or if the stomach is empty, liquid.
Regurgitation is less commonly seen. There are no signs that the pet is about to regurgitate – it just happens. If solid, the regurgitus is typically tube shaped as it comes from the back of the pharynx or the esophagus. It is a mixture of food, saliva and mucous, but there is no bile present. If no solid food is present, the regurgitus may be fluid, saliva, and mucus only
Here is a quick comparison of vomiting and regurgitation