A therapeutic substance used to counteract the toxic action(s) of a specific animal toxin (see TOXINS) or venom. They are normally sterilised, proteinaceous globulins (see GLOBULIN) extracted from the SERUM of animals, usually horses, immunised against the specific toxin/venom. Most are given by intravenous or intramuscular injection and are most effective when given shortly after the bite or sting has occurred. Some antivenoms may be effective against the venoms of several closely related animal species.