A decrease in total sperm count, sperm motility and weight of testes were observeb in the rats administered with benzene extract of leaves of o.sactum . the-term feeding of fresh leaves of tulsi had shown to decrease the sperm count and motiliy as well as decrese in the weinght of testes, epididymis, seminal vesicle, and ventral prostate . in another study performed on rabbits, a significant decrease in the sperm count was observed in rabbits supplemented with fresh leaves of /o.sanctum.Serum testosterone levels showed marked increase while FSH and LH levle were singnificantly reduced in o.sanctum-treated rabbits. the results suggest the potential use of o.sanctum as an effective male contraceptive agent .