Chaetoviridin A, an azaphilone isolated from Chaetomium sp., is a potent antifungal against plant pathogenic fungi in vitro and in vivo, suppressing the development of rice blast and wheat leaf rust by over 80% at a concentration of 62.5 mcg/mL. Chaetoviridin A has antitumor properties and inhibits tumor promotion induced by 12-O-tetradecanoylphorbol-13-acetate via an anti-inflammatory effect. Chaetoviridin A has moderate inhibitory activity against cholesteryl ester transfer protein (CETP).