This experimental trial was designed to evaluate the anti-Limnatis nilotica effect of Achillea millefolium L. ethanolic extract as well as levimisole and niclosamide. In an experimental study the extract of Achillea millefolium L. aerial parts was prepared and then the severity effect of the treatments was recorded and compared with placebo group on L. nilotica as anti-leech assay. The average time of paralysis and death of L. nilotica for Levamisole, niclosamide and Achillea millefolium L. plant were 12.66±5.19 min, 19.22±3.42 min and 90±17 min, respectively. Distilled water was determined as the inert for control group. In this study, it was determined that Achillea millefolium L. plant with an intensity of 3+ have a good anti-leech effect and can be shown to be effective in cases of leech bitings.