Black breast milk due to minocycline therapy.

We report the unusual case of a 29-year-old female who developed black discoloration of breast milk 3 weeks after commencing oral minocycline therapy for acne vulgaris. Histochemical analysis of the breast milk revealed the presence of pigment particles within macrophages with iron staining characteristics. We propose that the pigment may represent an iron chelate of minocycline or one of its derivatives.