Abstract: The study showed that both the aqueous and the stachydrine extracts of Leonurus heterophyllus’s root, stem and leaf had good effect on controlling Oncomelania hupensis, but their toxic activity was somewhat slower than that of niclosamide. The effect was in the sequence of leave＞stem＞root. After treated with the aqueous extracts of L. heterophyllus, the esterase isoenzyme activity of O. hupensis was higher than that of the control in 1-2 days, but decreased markedly in 3-4 days. During this process, some new bands of the enzyme appeared, and some bands disappeared. This change was mainly occurred in positive area, which accorded with the normal pathological reaction.

Key words: Soil organic matter, Models, Comparison