Aim: To observe the effect of the aqueous extract of hypocotyls of the plant Lepidium meyenii (Maca) on spermato-genic damage induced by the organophosphate insecticide malathion in mice. Methods: Mice were treated with 80 mg kg~(-1) of malathion in the presence or absence of an aqueous extract of Maca, which was orally administered 7, 14 or 21 days after injection of the malathion. Stages of the seminiferous epithelium were assessed by transillumination on days 0, 7, 14 and 21. Results: The administration of Maca increased significantly the length of stage 鈪?on days 7, 14 and 21 of treatment compared with the controls. An increase in the length of stage 鈪?occurred on day 14 of treatment. Malathion affected spermatogenesis by reducing the lengths of stage 鈪?on day 7, stages 鈪?and 鈪?鈪?on day 14 and a recovery of stages 鈪?鈪?on day 21. The magnitude of alteration in the length of stage 鈪?produced by malathion was significantly reduced by Maca on days 7 and 14. The length of stage 鈪?was increased when Maca was administered to mice treated with malathion. Assessment of the relative length of stages of the seminiferous epithelium showed that Maca treatment resulted in rapid recovery of the effect of malathion. Conclusion: Maca enhances spermatogenesis following spermatogenic damage caused by the organophosphorous pesticide. Aim: To observe the effect of the aqueous extract of hypocotyls of the plant Lepidium meyenii (Maca) on spermato-genic damage induced by the organophosphate insecticide malathion in mice. Methods: Mice were treated with 80 mg kg -1 of malathion in the presence or absence of an aqueous extract of Maca, which was orally administered 7, 14 or 21 days after injection of the malathion. Stages of the seminiferous epithelium were assessed by transillumination on days 0, 7, 14 and 21. Results: The administration of Maca increased significantly length of stage 鈪? on days 7, 14 and 21 of treatment compared with the controls. An increase in the length of stage 鈪? occurred on day 14 of treatment. Malathion affected spermatogenesis by reducing the lengths of stage On day 7, stages and? And 鈪? 鈪? On day 14 and a recovery of stages The? 鈪? On day 21. The magnitude of alteration in the length of stage produced? Produced by malathion was significantly reduced by Maca on days 7 and 14. The length of stage 鈪? was increased when Maca was administered to mice treated with malathion. Assessment of the relative length of stages of the seminiferous epithelium showed that Maca treatment derived in rapid recovery of the effect of malathion. Conclusion: Maca enhances spermatogenesis following spermatogenic damage caused by the organophosphorous pesticide.