MANY DRUGS can cause intense hemolysis when administered to individuals whose red blood cells (RBC) are deficient in glucose-6-phosphate dehydrogenase (G-6-PD).1One of these, nitrofurantoin (Furadantin) has also been suspected on at least two occasions of being etiologically associated with the development of megaloblastic anemia.2,3In the case described below, severe anemia with both intense hemolysis and megaloblastic erythropoiesis promptly followed the ingestion of nitrofurantoin by a previously nonanemic pregnant Negro woman. The anemia was rapidly corrected when the nitrofurantoin therapy was stopped and folic acid was administered. Report of a Case A 22-year-old Negro woman, pregnant for the fourth time, was first seen during this pregnancy in Prenatal Clinic on Aug 18, 1964, when about 27 weeks pregnant. During her third pregnancy two years before, numerous blood studies had been carried out as part of an extensive survey of the maternal hematologic changes associated with twinning. She