Sterols　are　the　important　active　ingredients　of　fungal　secondary　metabolites　to　induce　death　of　tumor　cells.　In　our　previous　study,　we　found　that　ergosterol　peroxide　(5a,　8a-epidioxiergosta-6,　22-dien-3　beta-ol),　purified　from　Ganoderma　lucidum,　induced　human　cancer　cell　death.　Since　the　amount　of　purified　ergosterol　peroxide　is　not　sufficient　to　perform　in　vivo　experiments　or　apply　clinically,　we　developed　an　approach　to　synthesize　ergosterol　peroxide　chemically.　After　confirming　the　production　of　ergosterol　peroxide,　we　examined　the　biological　functions　of　the　synthetic　ergosterol　peroxide.　The　results　showed　that　ergosterol　peroxide　induced　cell　death　and　inhibited　cell　migration,　cell　cycle　progression,　and　colony　growth　of　human　hepatocellular　carcinoma　cells.　We　further　examined　the　mechanism　associated　with　this　effect　and　found　that　treatment　with　ergosterol　peroxide　increased　the　expression　of　Foxo3　mRNA　and　protein　in　HepG2　cells.　The　upstream　signal　proteins　pAKT　and　c-Myc,　which　can　inhibit　Foxo3　functions,　were　clearly　decreased　in　HepG2　cells　treated　with　ergosterol　peroxide.　The　levels　of　Puma　and　Bax,　pro-apoptotic　proteins,　were　effectively　enhanced.　Our　results　suggest　that　ergosterol　peroxide　stimulated　Foxo3　activity　by　inhibiting　pAKT　and　c-Myc　and　activating　pro-apoptotic　protein　Puma　and　Bax　to　induce　cancer　cell　death.