Although it is secreted into breast milk it has not been detected in infant’s blood because it forms non-absorbable chelate compounds with milk calcium. It is not convenient a prolonged use (more than 3-4 weeks) since damage on bone growth plates, teeth discoloration, or alteration of intestinal flora may occur. Breast secretion can be black in color. Be aware of the possibility of false negative results of bacterial cultures when the mother is on antibiotics.