Tenuazonic acid is one of the major Alternaria mycotoxins commonly found as a natural contaminant in food. Tenuazonic acid contamination has been linked to esophageal cancer in human populations at risk of high exposure. Tenuazonic acid inhibits protein synthesis by suppression at the ribosome. Tenuazonic acid was shown to inhibit 12-O-tetradecanoyl phorbol-13-acetate (TPA) induced ornithine decarboxylase (ODC) activity in a mouse model, and in turn suppressed mouse skin tumor promotion. In addition, this compound has been shown to be a new type of Photosystem II inhibitor.