OBJECTIVE To describe our experience of dealing with patients admitted as emergencies after massive ingestion of hydrochloric acid, and to find out the most important prognostic factors. METHODS Retrospective review. METHODS Teaching hospital, Spain. METHODS 21 patients with massive necrosis of the upper gastrointestinal tract after ingestion of acid who presented during the past 14 years (November 1984-March 1998). METHODS All patients were operated on immediately, 17 without an endoscopic examination. In all cases, the laparotomy showed various degrees of damage to the intra-abdominal oesophagus (from oedema to blackening) and gastric necrosis. Twelve patients also had necrosis of the entire duodenum. In the other nine, the necrosis did not affect more than the pylorus or duodenum. All these 12 patients were treated by a total oesophago-gastrectomy without thoracotomy. Of the 12 patients with total necrosis of the duodenum, 4 did not have resections and in 8, various massive resections of the necrotic structures were done. METHODS Mortality. RESULTS Fourteen of the 21 patients died during the operation or in the early or late postoperative period. All 12 patients with total duodenal necrosis died, whereas only 2 patients in the other group. CONCLUSIONS The ingestion of relatively small amounts of water-based solutions of hydrochloric acid of 24% or 32% concentration produces immediate and massive necrosis of the upper digestive tract, which results in high mortality. The poor prognosis might be improved by rapid responses to stop duodenal necrosis.