The published data on the toxicity of hexachlorophene in animals and man are discussed. Studies performed in the author's laboratory including hexachlorophene blood level determinations in animals and man are also reviewed. Hexachlorophene can produce paralysis in rats, rabbits, cats, and pigs and blindness in sheep. Microscopic examination of the brains of rats and monkeys given repeated doses of hexachlorophene shows status spongiosus of the white matter and normal gray matter. Small amounts of hexachlorophene are absorbed through the skin of animals as well as man. Aside from the neurological effects of hexachlorophene, the chemical uncouples oxidative phosphorylation which may cause body temperature elevation.