The methanol extract from Salvia miltiorrhiza Bungee showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535 / pSK1002 against the mutagen, Trp-P-1, which requires liver metabolizing enzyme. The methanol extract was successively re-extracted with dichloromethane, butanol, and water. Three suppressive compounds were isolated by SiO2 column chromatography from dichloromethane fraction and identified as tanshinone IIA (1), tanshinone I (2) and Cryptotanshinone (3) by GC, GC-MS, 1H- and 13C-NMR spectroscopy. Compounds 1, 2 and 3 inhibited the SOS-inducing activity of Trp-P-1 in the umu test. Gene expression was suppressed by 76%, 96% and 81% at less than 0.18 μmol / mL, 9 respectively. The ID50 (50% inhibition dose) values were 0.03 μmol / mL 0.008 μmol / mL and 0.010 μmol / mol, respectively. These compounds were assayed with activated Trp-P-1. Compound 2 showed suppressive effect of SOS-inducing activity of activated Trp-P-1 but compounds 1 and 3 did not.