The inhibitory activity of tanshinones from Salvia miltiorrhiza was tested on rat liver diacylglycerol acyltransferase (DGAT). Cryptotanshinone (1) and 15,16-dihydrotanshinone I (3) exhibited potent DGAT inhibitory activities dose-dependently with $IC_{50}$ values of $10.5 {;}{mu extrm{g}}/ml{;}and{;}11.1{;}{mu extrm{g}}/ml$. However, tanshinone IIA (2) and tanshinone I (4) showed very weak inhibition ($IC_{50}{;}value:{;}>{;}250{;}{mu extrm{g}}/ml$). A dihydrofuran moiety was seemed to be responsible for the stronger inhibitory activity