It is estimated that approximately 20-30% of veterinary visits in companion animals are related to vomiting and/or diarrhea. This lecture presents a focused and systematic approach to identifying and classifying gastrointestinal signs. Particular attention will be placed on creating a focused differential list that helps prioritize diagnostics and empirical treatments. A diagnostic plan that does not include ultrasound or endoscopy will be presented. Accessible treatment options, such as diet trials, fiber supplementation, cobalamin, empirical steroid trials, synbiotics, and fecal transplants will be discussed, with evidence from the recent literature supporting their indications and use.