Abstract The principal Southern African colubrine and viperine venoms are described. Figures are given relating to the yield of venom by average specimens of the most important genera and species. The relative toxicities of the different venoms have been ascertained on a large variety of mammals and birds, the comparative susceptibility of which may be deduced from the tables. The reaction to venoms of carnivores such as mongooses and meercats, and rodents such as squirrels is dealt with. The relation between the toxic and antigenic properties of the venoms is discussed. Reasons are given for selecting the venoms of the Bitis arietans (Puff adder) and Naiaflava (Cape cobra) as the most desirable antigens to be converted into anavenoms both as regards polyvalent group action and the high neutralizing value of the resulting antivenene.