Objective: To investigate the influence of scutellarin on the activities of CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 in rats in vivo. Methods: Scutellarin and saline were intravenously administered to male Wistar rats via the caudal vein for 7 days consecutively. On the 8th day, the rats were treated with probe drugs of caffeine (10 mg/kg), tolbutamide (10 mg/kg), metoprolol (20 mg/kg), dapsone (10 mg/kg) by intraperitoneal injection, and the blood samples were collected at different times. The probe drugs in the blood samples were measured by ultra performance liquid chromatography mass spectrometer (UPLC-MS/MS) and the changes of the pharmacokinetics parameters of the drugs were observed to evaluate the effects of scutellarin on the four CYP450 isoforms in rats. Results: The activity of CYP1A2 in rats was inhibited significantly after treatment with scutellarin by increased caffeine t(1/2) (21.76%, P < 0.05), T-max (43.05%, P < 0.05), C-max (43.92%, P < 0.01) and AUC(0-infinity) (50.88%, P < 0.01) in the scutellarin-treated group compared with those of the blank control. The activity of CYP2C11 in rats was inhibited significantly after treatment with scutellarin by increased tolbutamide t(1/2) (16.74%, P < 0.01), T-max (116.87%, P < 0.05), C-max (63.78%, P < 0.01) and AUC(0-infinity) (70.61%, P < 0.01) in the scutellarin-treated group compared with those of the blank control. The activity of CYP3A1/2 in rats was inhibited significantly after treatment with scutellarin by increased dapsone t(1/2) (45.28%, P < 0.05), T-max (81.55%, P < 0.05), C-max (155.58%, P < 0.01) and AUC(0-infinity) (176.35%, P<0.01) in the scutellarin-treated group compared with those of the blank control. The pharmacokinetic parameters of metoprolol were not significantly changed in the scutellarin-treated group compared with those of the blank control. Conclusion: Scutellarin could significantly inhibit CYP1A2, CYP2C11 and CYP3A1/2 activities in rats in vivo, but had no effects on the activity of CYP2D1.