Flavokawain C is a chalcone that has been found in kava and has enzyme inhibitory and anticancer activities.^1,2,3 It inhibits collagenase and elastase in cell-free assays (IC50s = 62.05 and 17.6 µM, respectively).¹ It is cytotoxic to HCT116, HT-29, MCF-7, A549, and Ca Ski cancer cells (IC50s = 12.75, 39, 47.63, 40.28, and 39.88 µM, respectively).² Flavokawain C (20, 40, and 60 µM) induces apoptosis and cell cycle arrest at the G1 phase in HCT116 cells. In vivo, flavokawain C (1 and 3 mg/kg) reduces tumor volume and induces intratumoral necrosis and apoptosis in an HCT116 mouse xenograft model.³