Fumonisins are a group of mycotoxins recently discovered, toxic for humans and animals, produced by moulds of Fusarium like F. verticillioides, that grow on cereals and on by-products for human and animal consumption. Actually a strong attention is related to Fumonisin B1 for its toxicity and species-specificity in equine. In this species Fumonisin B1 is responsable of a neurotoxic form, Leucoencephalomalacia (ELEM) and a hepatotoxic ones. The mechanism of action is probably related to the similar structure of the mycotoxin to sphingosin, that is the basis of sphingolipid (sphingomyelin and glycosphingolipid), and a possible interference of Fumonisin B, in their biosynthesis. Actually different controversial aspects related to Fumonisin B1 and equine, on absorption or metabolism have to be clarified, taking into account different hypothesis.