A group of broad- spectrum ANTIBIOTICS which include oxytetracycline, tetracycline, doxycycline, lymecycline, minocycline, and demeclocycline.

All the preparations are active against both gram-negative and gram-positive bacteria (see GRAM'S STAIN). They are the treatment of choice for BRUCELLOSIS, LYME DISEASE, TRACHOMA, PSITTACOSIS, Q FEVER, SALPINGITIS, URETHRITIS and LYMPHOGRANULOMA INGUINALE, as well as for infections caused by MYCOPLASMA, certain rickettsiae (see RICKETTSIA) and CHLAMYDIA. Additionally they are used in the treatment of ACNE, but are not advised in children under 12 as they may produce permanent discoloration of the teeth. Similarly they are avoided if possible in pregnancy because the infant's milk teeth could be stained.