Gastroparesis is delayed gastric emptying of either solids or liquids, which occurs in the absence of mechanical obstruction. Although associated with many diseases, the most frequent cause of gastroparesis is diabetes mellitus. It is estimated that up to 50% of diabetic patients may have this problem. Symptoms of gastroparesis include postprandial nausea, epigastric pain/burning, bloating, early satiety, excessive eructation, anorexia and vomiting. The vomiting associated with gastroparesis often has the following two features: (1) emesis of undigested foods ingested more than four hours previous; and (2) emesis of undigested foods in the middle of the night or in the morning prior to eating breakfast. It is important to recognize and treat gastroparesis not only to decrease symptoms but also to prevent bezoar formation and nutritional deficiencies as well as to improve glycemic control in brittle diabetics. The purpose of this article is to review the physiology of gastric emptying and to use this information to understand the pharmacological therapies for this debilitating problem.