Scopoletin (SCT) is identified as a putative inhibitor of acetylcholinesterase (AChE). Scopoletin enhances the K-stimulated release of ACh from rat frontal cortex synaptosomes, showing a bell-shaped dose effect curve (Emax: 4 μM) . Scopoletin inhibits PC3 proliferation by inducing apoptosis of PC3 cells. The IC50 of Scopoletin for inhibiting PC3, PAA (human lung cancer cell), and Hela cell proliferation is (157±25), (154±51), and (294±100) mg/L, respectively. Scopoletin induces a marked time- and concentration-dependent inhibition of PC3 cell proliferation. Scopoletin reduces the protein content and decreases the acid phosphatase activity (ACP) level in PC3 cells in a concentration-dependent manner. Cells treated by Scopoletin show typical morphologic changes of apoptosis by light microscope, fluorescence microscope, and transmission electronmicroscope. Apoptosis rate is 0.3 %, 2.1 %, 9.3 % and 35 % for Scopoletin 0, 100, 200, and 400 mg/L, respectively, and cells in G2 phase decrease markedly after being treated with Scopoletin.