A cas is reported of a 23-year-old man who voluntarily took a massive dose of arsenic (at least 8 g). In spite of the ingested amount and the acute nature of the poisoning, the patient survived 8 days. Gastrointestinal, neurologic and cardiac features were predominant including nausea, vomiting, choleroid diarrhoea, encephalopathy, peripheral neuropathy, and finally a fatal toxic cardiomyopathy. Metabolic acidosis, moderate cytolysis and an anticoagulant effect were also observed. This unique characteristic was partly due to a circulating anticoagulant with prothrombinase activity, as well as direct antivitamin K activity. Postmortem examination revealed: a congestive oesophagitis; a necrosing gastritis involving all the stomach wall; diffuse hepatic steatosis; skin lesions with vascular congestion and dermoepidermal detachment; discrete subepicardial congestive lesions. Arsenic was found in all tissues.