Bloody diarrhea--a possible complication of sulfasalazine transferred through human breast milk.

Sulfasalazine very rarely causes bloody diarrhea. A 3-month-old infant had bloody diarrhea that could be related to sulfasalazine that had been taken by his mother and was transferred through his mother's breast milk. The patient was exclusively breast fed, and no other known etiological factors could be detected for the infant's bloody diarrhea.