Leonurus japonicus, commonly called Chinese motherwort, is a herbaceous flowering plant native to Asia, including Korea and Japan, and China to Cambodia. Plants are annual or biennial, growing from taproots. The stems are upright growing to a height of 30 to 120 cm. The flowers are sessile and produced in verticillasters. Three labdane diterpenes 15,16-epoxy-6-hydroxylabda-5,8,13(16),14-tretraen-7-one (leojaponin), (9α,13S);15,16-diepoxy-7β-hydroxylabd-14-en-6-one (13-epi-preleoheterin), and (9α,13R);15,16-diepoxy-6β-hydroxylabd-14-en-7-one (iso-preleoheterin) were isolated from the leaves of Leonurus japonicus, in addition to the previously reported preleoheterin. Functions: Smooth menses; Regulate menses; Invigorate blood circulation; Move blood; Reduce masses; Promote urination; Reduce swelling; Disperse phlegm; Disperse edema.