Acarbose is a novel oral anti-hyperglycemic agent approved for the treatment of noninsulin-dependent diabetes mellitus. It inhibits alpha-glucosidases in the small intestine, an action that delays the digestion and absorption of complex carbohydrates. Subsequently, there is a smaller rise in the postprandial plasma glucose levels and an overall decrease in the glycosylated hemoglobin by 0.5-1.0%. Potential advantages of acarbose include a greater effectiveness in controlling postprandial hyperglycemia, a low risk of hypoglycemia, and a possible delay in initiating insulin therapy. Acarbose can potentiate the hypoglycemic effects of sulfonylureas or insulin. It has not been associated with weight gain and hyperinsulinemia, both of which can occur with sulfonylureas or insulin. Gastrointestinal adverse effects are common with acarbose, and may decrease with continued treatment. Although rare, elevated serum transaminase levels have been reported.