Antivenoms to snake, spider, scorpion and jelly fish venoms are produced for the treatment of humans and animals, and for analytical use. The antivenom is purified with an antigen matrix containing a single whole venom or a plurality of whole venoms covalently attached to an insoluble support such as aldehyde-activated agarose. Preferably, the whole venoms forming the plurality of whole venoms are selected from the four whole venoms from C. atrox, B. atrox, C. adamanteus and C. durissus terrificus. A combination of immobilized C. atrox and C. durissus terrificus whole venoms can substantially purify antivenom reactive with all four venoms. The antivenom can be horse or avian such as chicken antivenom.