Bactrim(sulfamethoxazole/trimethoprim) is "maternal medication usually compatible with breastfeeding" according to the 1994 American Academy of Pediatric's committee on drugs, as reported in the 4th edition of Lawrence's BREASTFEEDING: A GUIDE FOR THE MEDICAL PROFESSION, page 707. comments on sulfamethoxazole are "In milk: about 1.2% of newborn dose. In first month, displaces bilirubin. Contraindicated in G6PD-deficient infants. Cow's milk: 50ppb. " Might want to inform mother and the physician of this! Natalie Shenk BS IBCLC Ohio USA