A nursing infant whose mother took alpha-methyldopa (alpha-MD) was followed for 3 months. Analysis of maternal serum and milk as well as the infant's serum and urine for alpha-MD revealed that the drug was excreted into maternal milk, absorbed by the infant and excreted in her urine, but no adverse clinical effects were noted during the follow-up period. alpha-MD is excreted in human milk in concentrations that probably do not harm the breast-fed infant.