Excreted into breast milk in quantities that would be clinically significant, however, intestinal absorption by infant's gut is hampered because of formation of chelating products by union with the milk's calcium. Tetracycline is at lesser amount excreted into breast milk and at higher proportion bound to calcium, hence, it is fewer absorbed than Doxycycline. Thus, it is a optimal alternative while breastfeeding. Long-term treatments are not recommended (over 3-4 weeks) since it may cause damage of the growth cartilage, teeth discoloration and imbalance of intestinal flora. Be aware of false negative results that may be obtained from infants with bacterial cultures when the mother is on antibiotics.