Lethal and hemolytic toxins were purified by acetone precipitation, Sephadex G-50, CM-cellulose and CM-Sephadex column chromatography from the tentacles and bodies of the sea anemone Actinia equina. The isolated toxins, with a mol. wt of 19,000 determined by SDS-polyacrylamide gel electrophoresis, differed only slightly in amino acid composition and had a high tryptophan content. The isoelectric points were estimated to be 9.8 for equinatoxin I and 10.5 for equinatoxins II and III. The pure toxins exhibited high lethal potency; the acute i.v. LD50 in mice of equinatoxins I, II and III were 23, 35 and 83 micrograms/kg, respectively. The sigmoidal time course of hemolysis is characteristic of toxins.