The 75% ethanol extract from roots of Salvia miltiorrhiza Bge. (Dan shen) afforded two new compounds, 3-hydroxy-2-(2'-formyloxy-1'-methylethyl)-8-methyl-1,4-phenanthrenedione (1), (8'R)-isosalvianolic acid C methyl ester (2), and 14 known compounds. Their structures were established on the basis of spectral analysis. The ability of the compounds to inhibit α-glucosidase activity and formation of advanced glycation end-products (AGEs) was evaluated. All compounds displayed various degrees of inhibitory effects against α-glucosidase; moreover, compounds 2, 6, 11, 14, and 16 exhibited much more potent inhibition against AGEs than the positive control (aminoguanidine, AG, IC(50) 0.11 μM). This is the first time that compounds from this plant have been reported to have inhibitory activity against α-glucosidase.