The hypoglycemic effects of water and butanolic extracts prepared from the bark of Acosmium panamense (Fabaceae) were studied in diabetic rats (streptozotocin (STZ)-induced). Oral application of water extracts at doses of 20 and 200 mg/kg and of butanol extracts at doses of 20 and 100 mg/kg significantly lowered the plasma glucose levels in diabetic rats within 3 h. Glibenclamide was used as reference and showed similar hypoglycemic effect like the extracts. Three structurally new compounds were isolated from the plant and shown to be the main constituents in both extracts.