Mycotoxins are substances toxic mushroom character with critical role in the pathological process. They act on the host cell protoplasm in extremely low concentrations by altering membrane permeability. Some toxins cause all or part of the symptoms. The most common toxin in many crop plants aflatoxin is produced by Aspergillus fungi genius. The basic structure of aflatoxins is the core cumatinic one condensed furan. Aflatoxins can exist in wheat, sesame, sweet potatoes, corn, rice, peanuts stored in improper conditions.