Fumonisins are toxic mycotoxins produced by Fusarium moniliforme, Fusarium proliferatum and Fusarium nygamoni. The structures of the fumonisins B1, B2, A1, A2 are a structurally closely related group of mycotoxins resembling the structure of natural sphingolipids. Fumonisins have been implicated as the causal agents in a variety of animal diseases and are epidemiological linked to the high incidence of human esophageal cancer in some regions in the world. Fumonisins are considered to be responsible for two distinct diseases in animals, namely equine leucoencephalomalacia (ELEM) in horses and porcine pulmonary edema (PPE) in swine. Examples of products in which fumonisins were detected are: maize, maize flour, maize bread, popcorn, rice, sorghum and beans. Fumonisins are heat stable compounds that survive under most conditions used during baking and frying. The Maximum Level in feed for animals is 5 mg/kg (5 ppm, horses), 10 mg/kg (10 ppm, swine) and 50 mg/kg (50 ppm, poultry and cattle). Officially until now no Maximum Levels (MLs) are recommended for fumonisins in Europe. Only Switzerland has a ML of 1 mg/kg (1 ppm) for Fumonisin in maize products. In the fumonisin EIA-kit of Euro-Proxima an antiserum is used that cross-reacts with Fumonisin B1 (100%), Fumonisin B2 (27%) and Fumonisin B3 (76%). The limit of detection for Fumonisin is 0.2 µg/kg (ppb).