The authors report a case of a forty-years-old woman who died nineteen hours after ingestion of a massive dose of Paraquat (about 125 ml of Gramoxone, 52 g of Paraquat) with vomitings, anuria and cardiac arrest. Early autopsy (less than two hours after death) showed necrotizing esophagitis, ulcerative gastritis, tubular nephritis, congestion of lung, interstitial myocarditis which could explain the heart failure. The ultrastructural study of lung showed interstitial edema associated with minimal endothelial changes but important epithelial cell necrosis of both pneumocytes. These findings are very similar to experimental studies of massive Paraquat poisoning emphasizing the early involvement of pneumocyte II.