The metabolites of baicalein in human plasma were investigated after taking baicalein, which is one of the main bioactive flavones in Scutellaria baicalensis Georgi. Five metabolites (M1-M5) together with the parent drug baicalein (P) were detected and identified by the HPLC-diode-array detector (DAD) and LC-MS/MS methods. Among them, 7-methoxybaicalein 6-O-glucuronide (M5) is a new metabolite. Based on the results, the proposed metabolic pathway of baicalein in humans was inferred.