Abstract: The n-butyl alcohol extracts of rhizoma of Dioscorea zingiberensis showed asignificant molluscicidal activity. Bloassay Alguided fractionation has led to the isolation oftwo molluscicidal steroidal sapoins: DZ1 and DZ3. With spectroscopic and chemicalmethods, DZIand DZ3 were determined to be gracillln and zingiberenin A, respectively.Among them,DZIhas a snail mortality of 98% at 5 mg/L in 72 hours,whlle DZ3 has amortality of 96 % at the same conditions. It is the first time the molluscicidal activities ofthese compounds were reported.