Many substances have been found to cause hemolytic anemia in persons whose erythrocytes are deficient in glucose-6-phosphate dehydrogenase (G6PD). However, the basis for the hemolysis observed with heavy metals has not been elucidated. In 1965, the author treated a patient who experienced severe acute hemolytic anemia after accidental ingestion of a saturated solution of copper sulfate. At that time, only one previous report1of copper sulfate-induced hemolytic anemia in man could be found. Subsequently, two papers2,3have documented several cases of copper sulfateinduced hemolytic anemia. It also has become apparent that this disorder has been repeatedly recorded in India. The case observed by the author is briefly recorded and investigations of possible mechanisms are described. Report of a Case A 22-year-old white woman inadvertently ingested an unknown amount of saturated copper sulfate solution. She vomited promptly and repeatedly. Diarrhea developed on the same day. Two days later she continued to