Objective To investigate the effect of uterine cavity injection of absolute ethanol on estrous cycle in mice.Methods Twenty mice with regular estrous cycle were selected by vaginal exfoliated cells staining, and then were injected absolute ethanol into their uterine cavity.The estrous cycle was observed and recorded every day.Ten mice were selected randomly to observe the changes of second estrous cycle every two hours.Results After the injection of absolute ethanol into the uterine cavity of the experimental mice, the estrous cycle was greatly prolonged, and the various degree of disorder was observed in estrus and pre-estrus.Conclusions The disorder was observed in estrous cycle of mice after the injection of absolute ethanol, which maybe provides some references for clinical use of absolute ethanol.