It can be concluded that fusarin C is a highly mutagenic metabolite with a mutagenic potency comparable to the potent mutagens aflatoxin B1 and sterigmatocystin. Fusarin C was shown to be a secondary metabolite of several strains of both F. moniliforme and F. graminearum but not of those strains of F. moniliforme var. subglutinans tested. It was proved to occur naturally in both F. moniliforme infected and "healthy" corn samples as the "fwin C" peak coincided precisely with that of authentic fusarin C. Even after exposure to long-wave W light, the HPLC chromatograms of the breakdown products of fusarin C and the isolated compound corresponded perfectly. In practice, the cooccurrence of fusarin C with the other Fusarium mycotoxins, moniliformin, deoxynivalenol, and zearalenone, in corn merits further investigation to determine any potential danger to human health. p-Hydrazinobenzoic acid (HBA) was identified in the cultivated mushrooms of the western hemisphere Agaricus bisporus. The commercial mushroom purchased locally was found to contain 10.7 ± 2.0 pg of HBA/g of mushroom (wet weight). HBA was quantitated in the fungus by high-performance liquid chromatography. The structure of HBA was confirmed by mass spectrometry. A new metabolite was purified from chloroform extracts of Claviceps paspali sclerotia by using column chromatography and preparative centrifugally accelerated, radial, thin-layer chromatography. The chemical structure of the metabolite was determined by ¹H and ¹³C NMR spectroscopy to be 4-(3-methyl-2-butenyl)paspalinine (paspalitrem C). Paspalitrem C differed from the previously identified tremorgen, paspalitrem A, only by the position of attachment of the 3-methyl-2-butenyl unit to the indole ring.