High performance thin layer chromatography (HPTLC) is used to rapidly determine the presence and amount of ergovalin in seeds ofGraminaceaeinfested withNeotyphodium Coenophialum.Quinine is used as an internal standard. The mycotoxin is solubilized under acid conditions and extracted with chloroform under alkaline conditions. Samples are sprayed on silica gel plates and detected by fluorescence with λ1(excitation) set at 318 nm and λ2(emission) > 400 nm.