A large proportion of the elements and their compounds have been associated with cases of poisoning in animals at some time, somewhere in the world. The main inorganic toxic hazards are well recognised and controlled, both by legislation and the high standard of quality control maintained by the animal feeds industry in this country. However, accidents can and do occur, in addition the more chronic effects caused by the prolonged ingestion of high levels of certain minerals and the interrelationships with other elements are not always appreciated. This paper described some of the inorganic toxic hazards in feeds which are most commonly associated with loss of animal production in this country, and the way in which problems arise: