This study was designed to examine the effect of Mori cortex radicis extract on cytarabine induced alopecia in young rat. cytarabine (50 mg/kg) was injected to Eight-day-old rats everyday for 7 days. After the injection, Mori cortex radicis extract was spread on the alopecia young rats for 12 days topically. The stimulative effect of hair growth was observed on 12th day of topical application. The stimulative effect of hair growth was best in MeOH extract group. And the same result was obtained in the experiment of hair follicle cross section.