In our former report we observed that cinnarizine influenced the antihypertensive effect of propranolol beneficially, but not of metoprolol in SHR and normal cat. Cardiac contractilities and smooth muscle relaxations induced by above drugs were measured to elucidate their mechanism of action. In cinnarizine and propranolol treated group, both of negative inotropic and ${eta}-blocking$ activity of propranolol in perfused rat hearts were increased and propranolol induced contraction in isolated arterial and trachea smooth muscle of the guinea pig was antagonized comparing to propranolol alone treated group. However, in the cinnarizine and metoprolol treated group, no significant differences in activity on the above were observed compared to metoprolol alone treated group.