Mutagenicity of residual chemicals on the skin of imported lemons was investigated by using the Ames test.　Their outer surface was rinsed with either acetone or dichloromethane. These solvents were evaporated and dried. To this, dimethyl sulfoxide was added to prepare for the Ames test. Experimental strains, TA98 and TA100, were obtained from the National Institute of Hygiene.　In the case of dichloromethane, both TA98 and TA100 showed positive reaction in both with and without S9 mix. On the other hand, in acetone, a similar tendency was observed, but not as distinct.