To the Editor.
—In the March Archives, Snider and Powell1 presented a well-organized review of the sparse and scattered data available in the literature concerning the appearance of antituberculosis drugs in human breast milk. The information available to these authors indicated that p-aminosalicylic acid and pyrazinamide were either not detectable or unknown at the time of publication; however, my laboratory has recently analyzed both of these components in human breast milk.A 27-year-old woman (non-breast-feeding) was given 4 g of p-aminosalicylic acid and breast milk collected at 0, 1, 2, 3, 4, 9, and 12 hours following oral administration. A maximum concentration of 1.1 mg/L was obtained at three hours with an elimination halflife of 2.5 hours. The maximum plasma concentration of the mother at two hours was determined to be 70.1 mg/L. Gastrointestinal tract irritation later developed and the p-aminosalicylic acid was withdrawn from the