The incidence of caustic ingestion varies with the availability of caustic products and preventive measures. A transient increase was seen in the US round 1970, in Denmark in the late seventies. Diagnosis and treatment of caustic ingestion injuries remains controversial, and must to a high degree be based on retrospective studies and animal studies, especially concerning the pathology and clinical course of the disease. These subjects are reviewed together with complications and prognosis. It is stressed, that ingestion of alkalies and acids result in a variety of lesions, depending on a number of factors listed. Ingestion of alkalies occurs in approximately 85% of all cases, with oesophageal stricture as the most frequent complication, and tracheal necrosis as the most frequent cause of death. Ingestion of acid in large amounts may lead to early gastric perforation, massive metabolic acidosis, and eventual death. Pyloric stenosis is the most common complication of acid ingestion. Approximately 33% of all patients admitted with (suspected) caustic injury reveal oesophageal damage. This leads to subsequent oesophageal stricture in 10-15%. Mortality is less than 10% in unselected groups.