Abstract: A decoction of Clerodendron bungei steud, its total alkaloids and magnesium lactate were found to be efficacious in treating prolapse of uterus. This paper reports their effect on electromyogram of ligament teres uteri in rabbit.The experiment has been carried out in seventy-one adult female rabbits anaesthetized with 0.5g/kg of urethan i. v. The change of electromyogram of the left ligament teres uteri was recorded with unipolar electrode conduction. Intravenous injections of decoction of Clerodendron bungei steud, its total alkaloids or magnesium lactate in doses of 15 g/kg, 45 g/kg and 27 mg/kg, respectively, were able to increase the strength of the electromyogram of ligament teres uteri in rabbits Noradrenaline was shown to have the same effect. This action can be blocked by previous injection of regitin iv, but not by propranolol. This result indicates that α-adrenergic receptor appears to increase the electromyogram of ligament teres uteri in rabbits. The total alkaloids and magnesium lactate which increase electromyogram of ligament teres uteri in rabbits may be relevant to the stimulation of the α-adrenergic receptor. Thus, one of the mechanisms of the effect of Clerodendron bungei steud on prolapse of uterus is likely to restore and increase the ligament tone.