The present study investigates the direct effects of Carum carvi L. (Apiaceae) ethanol extract on dispersed intestinal smooth muscle cells (SMC) of guinea pigs. Effects of the plant extract on SMC and of acetylcholine (Ach) on extract pretreated SMC were measured by micrometric scanning technique. Three different extract concentrations (2.5 mg/mL, 250 mug/mL, and 25 mug/mL) were used. Ethanol extract of C. carvi reduced significantly the response of dispersed SMC to Ach. Pretreatment of SMC with the highest concentration of C. carvi ethanol extract (2.5 mg/mL) has significantly inhibited the response of SMC to Ach. The data obtained indicate a dose-dependent inhibition of the contraction induced by Ach. This response may explain, in part, the beneficial effect of caraway in relieving gastrointestinal symptoms associated with dyspepsia.