This study was designed to demonstrate the antigenotoxic potential of methyl alcohol extracts from Auricularia mesenterica and Gyrophora esculenta against the frequency of micronucleate polychromatic erythrocyte(MNPCE) produced by benzo($alpha$) pyrene in vivo. We used the mouse bone marrow test system to measure the effect of single and multiple treatments of each sample. Genotoxicity of benzo ($alpha$) pyrene(150mg/kg, i.p.) as positive control was the highest at 36 hours. However, each sample per dose was not genotoxic, showing MNPCE values in the range of the control level. Treatments of methyl alcohol extracts both of Auricularia mesenterica and Gyrophora esculenta showed significant decreased frequencies of NMPCE induced by benzo($alpha$) pyrene within 12 hours by single treatment(100mg/kg, oral). And also, the MNPCE level produced benzo($alpha$) pyrene was decreased by the treatment of benzo($alpha$) pyrene(5 to 200mg/kg, oral) of each sample, but significantly different redults were obtained with 100mg/kg. In the multiple treatment, the highest antigentoxic effects were demonstrated with 20mg/kg in the each sample, a range which induced inhibition indices of 54.2 and 56.3%, respectively.