It has been generally understood that belladonna alkaloids in small doses produce bradycardia. However, it is also known that these agents increase heart rate during general anesthesia. In this study, a comparison of atropine and propantheline on human heart rate during ether anesthesia was made and the following results were obtained. 1) Atropine and propantheline increased heart rate. 2) Effect of propantheline on the heart rate was more marked than that of atropine.