Ergosterol peroxide (5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) is a steroid derivative.

It has been isolated from a variety of fungi, yeast, lichens and sponges,[1][2][3][4][5] and has been reported to exhibit immunosuppressive,[6] anti-inflammatory,[7] antiviral,[8] trypanocidal [9] and antitumor activities in vitro.

[10][11]