An in silico model of the stomach is presented to study the phenomenon of duodenogastric reflux. We use the model to investigate the role of pyloric incompetence, food properties, and gastroparesis on reflux. This first-ever in silico study of duodenogastric reflux provides new insights into the mechanisms and factors implicated in this reflux and the sequelae of conditions that result from the exposure of the stomach lumen to bile.