One of the most common reasons that pets end up in the veterinary hospital or ER is due to vomiting and diarrhea, known medically as gastroenteritis. While trauma and poisonings are common and more dramatic, this sometimes simple, sometimes complex condition accounts for a big percentage of veterinary visits. In some cases, the cause can be serious, elude diagnostics tests, or require hospitalization or surgery. Luckily for many cases, the cause and treatment are simple, and management can be completed at home. Your vet can help guide you through the steps needed to determine the cause and the best course of action, and some of the information here will help you decide what's best for your pet before a visit.