Patients with upper gastrointestinal disease can present with a diverse array of symptoms, which are linked to significant morbidity and relatively few reliable signs. Upper gastrointestinal pathology can present as an acute abdomen, for which clinical diagnostic accuracy is approximately 50%. The aim of this article is to provide a systematic approach for formulating a differential diagnosis in patients with common symptoms and signs of upper gastrointestinal disease, highlighting ‘red flags’ for serious pathology.