The fact that Napoleon Ist died from gastric cancer seems to be well established. Arguments for the hypothesis of chronic arsenic poisoning have recently been developed in the literature. This study, focused on the gastrointestinal diseases of Napoleon in Saint Helena, is based on a confrontation between the clinical semiological anamnesis and the anatomical data in the autopsy report by F. Antommarchi. Napoleon presented several gastrointestinal diseases: gall-bladder lithiasis complicated with angiocholitis, chronic colitis and certainly a gastric cancer. Death was consecutive to perforation of the gastric lesion leading to haemorrhagic vomitis and multiorgan failure. The description of the gastric lesions during autopsy is consistent with the diagnosis of cancer. The course of the clinical events is closely correlated with the anatomic lesions. There is strong evidence that Napoleon died from an acute complication of his gastric disease.