A fast solid phase extraction-high performance liquid chromatography-ion trap mass spectrometry (SPE-HPLC-MSn) method is presented for quantitative determination of 3-(3,4-dihydroxyphenyl)-2-hydroxylpropionic acid (Danshensu, DSS) from Compound Danshen Dripping Pills (CDDP) in rabbits' heart, liver, kidney, and lung and for qualitative analysis of the bioactive metabolites of Radix Salvia miltiorrhizae (DS) from CDDP in these tissues. The proposed method was validated with a detection limit of 0.06 ng/mL and a linear range of 5.0-200 ng/mL for DSS. The main metabolites of DS were pyrocatechol, vanillic acid, isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate, and 2-hydroxyl-3-(3,4-dihydroxyphenyl)propinonic sulfuric anhydride. In vitro pharmacological experiments demonstrated that isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate had a distinct vasodilatating action.