Cupper is an essential element for plants, animals and humans. Under certain circumstances, cupper excessive consumption could result in animal and human intoxication. In order to ensure safe and innocuous and safe foods for Mexicans, government create legislation as Norma Oficial Mexicana to establish the maximum levels of residues, particularly cupper in liver, kidney and muscle of human consumption animals. Liver in Mexico ruminant animals regularly contain 60 mg Cu/kg, which is the legal limit for this metal. This demands a review of the actual legislation. The strict application of this Norma will limit the commercialization of these viscera, since approximately 50% will exceed the legal limit for cupper. A potential hazard for human health, especially young people, is found in the constant ovine liver consumption feed with animal excretes with higher amount of supplementary cupper