Summary and Comments This report deals with the clinical effectiveness of carbarsone as an amoebicide when given orally in larger doses than usually recommended, and without any adjuvants or supportive treatment. Two series of patients are reported upon. One comprises thirty-five inmates in an asylum for the insane to whom forty-three treatments were given, and the other ten members of laboratory personnel and their families each of whom received only one course. In the former series there were six cases of acute amoebic dysentery and twenty-nine carriers, in the latter all were carriers. In no case were there any symptoms or signs of liver abscess or other lesions outside of the colon.