The ether extract of Salviae miltiorrhizae Radix(SMR) was fractioned to give five subfractions, so that two subfractions of them were recrystallized to yield each pure diterpene quinone pigment. On the basis of spectral evidence, these two compounds were identified as tanshinone II and crytotanshinone. Cryptotanshinone exhibited both of a potent platelet anti-aggregating activity in vitro and a potent antimicrobial activity. GC-MS analysis of the other extract showed that tanshinone II was contained in the largest proportion of all the diterpene quinones. In addition, GC-MS analysis gave other valuable analytical informations.