The effects of the essential oil of Alpinia speciosa Schum (EOAS) on rat ileum were studied. EOAS (0.1-600 mug/mL) reversibly relaxed ileal basal tonus, Submaximal contractions induced by 60 mM KCI or acetylcholine were concentration dependently inhibited by EOAS with similar IC50 values (similar to 44 and 48 mug/mL, respectively). These results show that EOAS possesses both relaxant and antispasmodic actions in the ileum, Copyright (C) 2000 John Wiley & Sons, Ltd.