Bile reflux upset stomach and nausea after eating chocolate is associated with increased bile secretion and increased gastric acid secretion. Bile reflux is a group of diseases in which bile refluxes into the stomach caused by dysfunction of the pyloric sphincter, damaging the gastric mucosal barrier and resulting in symptoms such as stomach distension, nausea, and vomit containing bile. Bile reflux stomach discomfort and nausea after eating chocolate is related to the following reasons. Chocolate is high in fat and promotes bile secretion. Because the breakdown of fat depends on bile salts in bile, eating chocolate promotes the secretion of bile and aggravates bile reflux, resulting in upset stomach and nausea. Sweets such as chocolate can lead to an increase in gastric acid secretion. In addition, foods high in fat and chocolate can lead to esophageal sphincter dysfunction or prolonged transient relaxation, resulting in nausea, acid reflux, and other gastric discomfort. Patients with bile reflux should avoid eating high-fat, sweet foods, etc. The most important thing is to follow the doctor’s instructions for regular treatment to avoid adverse effects.