Physalis philadelphicaLam, commonly known as a tomatillo, is a staple of the Mesoamerican cuisine. In our laboratory, an ethyl acetate-soluble extract and four withanolides [ixocarpalactone A (IxoA), ixocarpalac-tone B, philadelphicalactone B, and withaphysacarpin] were isolated. Stud-ies conducted on Hepa-1c1c7 hepatoma cells revealed that withanolides were potent inducers of quinone reductase, suggesting possible cancer chemo-protective activity.