The toxic action of various doses of carbon tetrachloride on the liver was determined. It was found that doses as small as 0.05 cc. per kilo produced hepatic lesions in some animals. These, however, are usually of a mild grade. This dose is therefore somewhere near the limits of safety. It was found that the simultaneous administration of magnesium sulphate decreased the toxic action of carbon tetrachloride on the liver. The protection offered by the simultaneous administration of magnesium sulphate is probably sufficient to place the usual therapeutic dose of 3 cc. for a human adult within the limits of safety. It is said that magnesium sulphate does not diminish the anthelmintic action of carbon tetrachloride. No definite changes were observed in the kidneys.