The author describes the phases of the antiophidian campaign in Minas Gerais (1918 to 1940). He registers the following species of poisonous snakes found: Bothrops cotiara, Bothrops alternata, Bothrops atrox, Bothrops neuwiedii, Bothrops jararaca, Bothrops inaequalis, Bothrops jararacussú, Crotalus terrificus terrificus, Lachesis mutus, Micrurus lemniscatus, Micrurus frontalis, Micrurus corallinus and numerous species not poisonous, making a map for the geographical distribution of the poisonous snakes in Minas Gerais. He verified that the species of the genus Bothorops and not of the genus Crotalus, predominate in the State. He registers morphologic differences principally in size of the Crotalus terrificus terrificus of the North of the State and of the Centre and South. He relates two cases of a cerain gravity of persons allergic to aphidian poison, liquid or dry; they were cured by being removed from the work of the snakes department of the Instituto Ezequiel Dias. He also registers, in 22 years of work numerous observations on the bites of poisonous and nonpoisonous snakes, the latter without gravity. of the first 984 observations were of human cases and of these 531 took serum with a mortality rate varying from 7,6 to 100% of the cases, according to the period and the kind of snakes; the general average death rate being 33%. No case of Lachesis mutus recovered.