Isolation and characterization of three new trichothecene mycotoxins from Fusarium sporotrichioides MC-72083 are reported. Structure and n.m.r. assignments were made using COSY, NOESY and INAPT as well as other spectroscopic techniques. The trichothecenes are a growing class of toxic sesquiterpenoids produced by a variety of fungi, including Fusarium, Stachybotrys, Trichothecium, Myrothecium and Cephalosporium'. They are responsible for alimentary toxic aleukia, vomiting, skin inflammation, weight loss and death in humans and agricultural animals.' Detailed studies 3,4 suggest that the toxicoses induced in animals by ingestation of Fusarium infected wheat are not related to the amount of the commonly occurring Fusarium mycotoxins (i.e. deoxynivalenol, zearalenone, etc.) present. This indicates that the toxicity may arise from new minor secondary metabolites and/or synergistic effects.5 Recent efforts in our laboratories directed at understanding this problem has yielded new relatively non-toxic trichothecenes. 697 In this paper we report the structures, spectral data and biological activities of three new toxic metabolites: an unusually oxidized trichothecene, a novel modified trichothecene, and the first reported trichothecene with a propionate ester group.