Even with the continuing emergence of new antibiotics, erythromycin continues to be used extensively in obstetrics and gynecology. It is inexpensive, with a long history of usage and proven safety. When oral erythromycin preparations are given in the correct dose and with proper timing in relation to meals, no individual preparation offers a significant therapeutic advantage. Its uses include the treatment of respiratory tract infections, chlamydial and other genital tract infections in pregnancy, puerperal mastitis, and acute conjunctivitis of the newborn.