Mycotoxins are produced in a strain-specific way, and elicit some complicated and overlapping toxigenic activities in sensitive species that include carcinogenicity, inhibition of protein synthesis, immunosuppression, dermal irritation, and other metabolic disorders. Mycotoxins usually enter the body via ingestion of contaminated foods, but inhalation of toxigenic spores and direct dermal contact are also important routes. In general, myctoxin exposure is more likely to occur in parts of the World where poor methods of food handling and storage are common, where malnutrition is a problem, and where few regulations exist to protect exposed populations. There is sufficient evidence from animal models and human epidemiological data to conclude that mycotoxins cause an important danger to human and animal health. The mycotoxins of major concern as feed contaminants are aflatoxins, ochratoxin A, T-2 toxin, zearalenone and fumonisins. Cytotoxicity and reactive oxygen species (ROS) generation are mechanisms of myctoxins mediated toxicity. The cell can tolerate a small to moderate amount of ROS by antioxidants molecules e.g. vitamin A, E and C, glutathione and the activities of catalase, superoxide dismutase, glutathione reductase, peroxidase and transferase. Trichothecenes cause protein synthesis inhibition via binding to the 18s rRNA of the ribosomal subunit as a major mechanism underlying induction of cell apoptosis. T-2 toxin triggers a ribotoxic response through its high binding affinity to peptidyl transferase which is an integral part of the 60s ribosomal subunit and interferes with the metabolism of membrane phospholipids and increases liver lipid peroxides. Thiol (-SH) is thought to induce caspase-3 activation and apoptosis in a GSH-sensitive manner. FB1-induced inhibition of ceramide synthesis can result in a wide spectrum of changes in lipid metabolism and associated lipid-dependent pathways. OTA has complex mechanisms of action that include mitochondrial impairment, formation of OTA-DNA adducts and induction of oxidative stress and apoptosis through caspase activation. Accordingly, the strict control of food quality is necessary to avoid mycotoxicosis.