Motherwort contains leonurine. The uterotonic effect of leonurine was demonstrated in rat uterus in vitro.
– Am J Chin Med 1976 WINTER;4(4):373-82 — Isolation of the uterotonic principle from Leonurus artemisia, the Chinese motherwort. — Kong YC, Yeung HW, Cheung YM, Hwang JC, Chan YW, Law YP, Ng KH, Yeung CH.

May cause a decrease in blood pressure.
– J Ethnopharmacol 2002 Apr;80(1):85-90 — Pharmacological effects of lavandulifolioside from Leonurus cardiaca. — Milkowska-Leyck K, Filipek B, Strzelecka H.

Motherwort (Leonurus sibiricus) has stimulating action on the uterus.
– Zhongguo Zhong Yao Za Zhi 1995 Mar;20(3):173-5, 192 — Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus — Shi M, Chang L, He G.