Ovarian cancer remains to be the top reason to threaten the human health, and clinical utilization of trametinib for the treatment of ovarian cancer has been frequently reported. The recent study aims to determine the inhibition of trametinib towards the activity of UDP-glucuronosyltransferase (UGT) 1A7, trying to indicate potential drug-drug interaction (DDI). Recombinant UGT1A7-catalyzed 4-methy-lumbelliferone (4-MU) glucuronidation was used as the probe reaction to evaluate the inhibition of trametinib on the activity of UGT1A7. Trametinib 100 mu M of significantly inhibited UGT1A7-catalyzed glucuronidation metabolism of 4-MU. Furthermore, concentration-dependent inhibition of trametinib on the activity of UGT1A7 was demonstrated. In the Lineweaver-Burk plot, the intersection point of all the lines was located in the horizontal axis, indicating the noncompetitive inhibition of trametinib on UGT1A7. In the second plot, the slopes of the lines in the Lineweaver-Burk plot were drawn versus the concentrations of trametinib, and the fitting equation was y = 0.0352x + 1.1591. Based on the fitting equation, the inhibition kinetic parameter (Ki) was calculated to be 32.9 mu M. In conclusion, all these results indicated the potential drug-drug interaction (DDI) between trametinib and clinical drugs mainly undergoing UGT1A7-catalyzed metabolism.