OBJECTIVE To describe the clinical and endoscopic features of caustics injuries in the upper gastrointestinal tract in patients of the National Hospital Daniel Alcides Carrión. METHODS A descriptive study was conducted; the study populations were patients diagnosed with caustic ingestion who were admitted into the Gastroenterology service of the HNDAC to perform an upper endoscopy during the period of January 2009 to December 2012. We documented the type of caustic substance ingested, cause of intake, amount ingested, intake mode, signs or symptoms present, endoscopic findings as classified by Zargar, presence of complications and treatment performed. Analysis was performed comparing them based on the ingested caustic type: acid or alkali. RESULTS We obtained 91 patients; the average age was 30.6±16.3 years. Caustic substances ingested were: bleach (sodium hypochlorite) in 71 (78%) patients, muriatic acid (hydrochloric acid) in 18 (20%) patients, caustic soda in 2 (2%) patients. The average intake was 136ml (30-500 ml). The most frequent signs and symptoms were vomiting, abdominal pain, nausea and sore throat. The 46% of patients had injuries. 100% of patients who ingested acid and 33% who ingested alkali had lesions. Five (5%) patients had oropharyngeal lesions, 24 (26%) in the esophagus, 36 (40%) in the stomach and 12 (13%) in the duodenum. Grade I lesions were found in 10 (11%) patients, 16 (18%) patients with grade II lesions and 15 (16%) of patients with grade III, 12 patients who toke acid had lesions of grade III. Esophageal stricture was found in 2 (2%) patients, gastric stenosis in 7 (8%) patients and esophageal and gastric stenosis in 3 (3%) patients. Two patients required pneumatic dilation and 10 surgical treatments. CONCLUSIONS Most injuries were found in the stomach. Acidic injuries occur more frequently and with greater severity than alkaline. Acidic substances produce esophageal or gastric stenosis more frequently than alkaline.