The effect of Annona muricata leaves extract on the estrous cycle was studied. Four treatments of this extract were caried out with 0%, 5%, 10% and 15% concentrations respectively. Vaginal smears were used to determine the estrous cycle by microscopic examination of the epithet cells. The result showed that 10% dosages of A. muricata leaf extract is the most effective in shorting the estrous cycle of mice, namely 3.75 days, whereas the other dosages showed much longer estrous cycles of more than 4 days
