LOFROTH observed that the average breast-fed baby in the United States ingests twice the amount of DDT deemed safe by the World Health Organization (0.010 mg), while corresponding Swedish and British infants consume 0.017 mg of DDT compounds per day per kg body weight1. We have studied the effects of DDT on neonatal Holtzman rats housed in individual cages at 25±1.0° C and allowed Purina Lab Chow with drinking water ad lib. Forty parturient rats were divided into four groups of ten. Group 1 served as controls, group 2 received 1 mg, group 3 received 5 mg and group 4 received 25 mg of Technical DDT (Cl3CCH(C6H4Cl)2) (Eastman Organic Chemicals) per kg body weight, starting 24 h after delivery and daily for 21 days thereafter. DDT in sesame oil was administered to the experimental groups intraperitoneally. Control animals received only the sesame oil vehicle. After evaluation of growth and mortality rates, the animals were killed and calcium, potassium, magnesium, manganese, copper, iron and zinc in neonatal livers were determined by atomic absorption spectrophotometry2.