In 4 cases of fulminating hemolytic anemia in young children observed during a period of two years the ingestion of moth balls consisting of pure naphthalene (C10H8) was the sole apparent etiologic factor. Experimental studies in dogs confirmed the hemolytic action of naphthalene. Since moth balls are a common and easily accessible household article, generally believed to be harmless, and since the American literature seems to contain no previous reports of this kind, the cases are reported in detail. REPORT OF CASES Case 1.— A. W., a Negro girl aged 2 years, was admitted to the Children's Hospital of Michigan with the chief complaint of passing wine-colored urine. She had been entirely well until four days prior to admission, at which time she had diarrhea and seemed generally ill. The next day she became lethargic and passed urine of greenish tinge. The following day she refused nearly