Successful investigation and prevention of mycotoxic problems requires close collaboration between scientists from several disciplines ranging from agronomists and technologists required during production of food and feeds, to toxicologists and pathologists examining the effects of mycotoxins on animals and man. Zootoxic metabolites following fungal infection result from four general mechanisms: (i) secondary fungal metabolism (mycotoxins, eg, aflatoxins); (ii) bioconversion of vegetal compounds (eg, dicoumarol); (iii) plant reactions (phytoalexins, eg, coumestrol); and (iv) plant-fungus associations (endophytes, eg, Acremonium/Festuca). In reported pathologic field cases, close cooperation through a selected veterinary network has allowed diagnosis of acute and subacute mycotoxicoses in France. Natural stachybotryotoxicosis may not be limited only to cold climates, but may also occur in mild and warm ones (eg, south west of France, Morocco). A considerable variation was observed in symptoms and lesions depending on toxin levels, ranging from a poor performance in a horse race to a general haemorrhagic syndrome. Several cases of acute equine leucoencephalomalacia, characterized by pathognomonic lesions and recently supported by fumonisin analysis, have been diagnosed in the southern part of France and other countries (eg, New Caledonia and the Ivory Coast). Facial eczema in sheep is endemic in the Basque country, as a result of specific bioclimatic and zootechnic conditions. Reproductive disorders in sheep, cattle, goats and rabbits have been associated with high levels of coumestrol in alfalfa, clover and their derivatives. A few cases of fescue foot disease, associated with the endophyte Acremonium, have been diagnosed recently. In addition, several nervous disorders may be due to unknown mycotoxins. These acute or subacute mycotoxicoses suggest a potentially widespread occurrence of low level toxins and insidious asymptomatic mycotoxicoses, and justify interdisciplinary research in order to improve diagnosis and preventative measures.