A case of chronic arsenic intoxication due to ingestion of contaminated water for several years is reported. The main symptoms were keratosis palmaris et plantaris, confetti - Like dyschromias in chest, post - necrotic liver cirrhosis multiple intraepithelial epidermoid carcinomas and invasive epidermoid carcinoma. The epidemiologic study showed high concentration of arsenic in the water of the well used by the patient; likewise, chronic arsenicalism was found in the whole family and in several neighbors who consumed water from the same well.