Fumonisins are natural contaminants mainly of maize grains and derived products worldwide. Fumonisins are produced by species of Fusarium genus, mostly F. verticillioides and F. proliferatum. The most abundant species in nature is Fumonisin B1 (FB1), followed by Fumonisin B2 (FB2) and fumonisin B3 (FB3). They and are carcinogenic to animals and potentially also to humans. Typical toxicoses caused by fumonisins are leukoencephalomalacia in horses and pulmonary edema in pigs. They are also suspected to play a role in esophageal cancer in humans (IARC group 2B). The European Commission has regulated the occurrence of fumonisins in food and feed products with special emphasis to maize and derive products and other cereals.