The most frequent toxigenic fungi in Europe are Aspergillus, Penicillium and Fusarium species. They produce aflatoxin B1 transformed into aflatoxin M1 found in the milk, as well as Ochratoxins and Zearalenone, Fumonisin B1, T-2 toxin, HT-2 toxin and deoxynivalenol (vomitoxin), which are of increasing concern in human health. These mycotoxins are under continuous survey in Europe, but the regulatory aspects still need to be set up and/or harmonised at European level. They are found in foodstuffs and are not destroyed by normal industrial processing or cooking since they are heat-stable. Some of their metabolites are still toxic and may be involved in human diseases. Their toxic effects (liver, kidney and hematopoetic toxicity, immune toxicity, reproduction toxicity, foetal toxicity and teratogenicity, and mainly carcinogenicity) are mostly known in experimental models, the extrapolation to humans being always inaccurate. The inaccuracy of extrapolation to humans may be explained by the lack of adequate food consumption data, lack of knowledge about relative health risks associated with specifically proposed limits and by the possibility of synergism with other mycotoxins present in the same food commodities. Other pathological causes are viral hepatitis, immune or hormonal deficiencies or organ dysfunction. Even when a specific biomarker of a given mycotoxin is identified in humans, it remains difficult to establish the relation with a given illness, because of genetic polymorphism and the possible beneficial influence of diet, and because other environmental toxicants may well interfere. The acceptable daily intake limits are mostly based on animal data and may be too high, due to the differences in the sensitivity of different animal species. The prevention involves first reduction of mycotoxin levels in foodstuffs and further increasing the intake of diet components such as vitamins, antioxidants and substances known to prevent carcinogenesis.