Bile reflux is usually caused by a dysfunction of the pyloric portion of the stomach, or by a dysfunction of the unidirectional contraction of the pyloric sphincter. 1. Dysfunction of the pylorus of the stomach: Under normal conditions, bile passes through the bile ducts and from the gallbladder into the duodenum. The duodenum is connected to the stomach at a point called the pylorus, which serves to transport the stomach contents into the duodenum. When the pylorus is dysfunctional, the bile present in the duodenum refluxes into the stomach, causing bile reflux. 2. Dysfunction of the pyloric sphincter: Dysfunction of the pyloric sphincter affects the contraction of the pyloric muscle. When the pyloric sphincter loses the ability to maintain unidirectional movement, the alkaline bile present in the duodenum will reflux into the stomach, thus causing bile reflux. When bile reflux occurs, gastric mucosal ulcers, bloating, nausea, etc., please seek prompt medical attention for proper examination.