In this present study, effects of aqueous extract of Elletaria cardamomum on isolated frog heart and rectus abdominus muscles were studied. The extract was prepared by maceration and its effect was studied for various doses. Results show that aqueous extract of Elletaria cardamomum, dose dependently decreases the heart rate and force of contraction. To assess the probable cause of cardiac depressant action, K+ content was assessed by using flame-photometer. The study of the aqueous extract on the rectus abdominus muscles resulted in smooth muscle relaxation, indicating involvement of muscarinic receptors. The effect of extract was significantly blocked in the presence of atropine, supporting the involvement of muscarinic receptors. The extract has also showed vasodilatory effect in hind limb perfusion experiment. From these studies, we concluded that Elletaria cardamomum has cardiac depressant effect, which might be due to the presence of muscarinic principles.