Clinical observation on the uterotonic effect of I-mu Ts'ao (Leonurus artemisia)

Normal fertile women given an oral dose of I-mu Ts'ao decoction (30 g. dry weight equivalent) showed an increase in intra-uterine pressure in 41.3% of 121 cases. The increase ranged from 150% to over 300% of spontaneous activity before dosing. A slightly higher success rate was observed with 2 successive doses or with improved experimental skill in later cases. Ergonovine (0.2 mg i.m.) scored a success rate of 61%. Therefore, I-mu Ts'ao decoction appeared to have a relative potency of 91% compared with ergonovine when the highest success rate (55.5%) of the former is considered. Blank control with water yield a positive response rate of 2.7%. There are no observable side-effects apart from diuresis.