Doxycycline is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc.^{[citation needed]} and marketed under the brand name Vibramycin.^{[citation needed]} Vibramycin received U.S. Food and Drug Administration approval in 1967,^{[citation needed]} becoming Pfizer's first once-a-day, broad-spectrum antibiotic.^{[citation needed]} Other brand names include Monodox, Microdox, Periostat, Vibra-Tabs, Oracea, Doryx, Vibrox, Adoxa, Doxyhexal, Doxylin, Doxoral, Doxy-1 and Atridox (topical doxycycline hyclate for periodontitis).

In addition to the general indications for all members of the tetracycline antibiotics group, doxycycline is frequently used to treat chronic prostatitis, sinusitis, syphilis, chlamydia, pelvic inflammatory disease,acne, rosacea, and rickettsial infections.

It is used in prophylaxis against malaria. It should not be used alone for initial treatment of malaria, even when the parasite is doxycycline-sensitive, because the antimalarial effect of doxycycline is delayed. This delay is related to its mechanism of action, which is to specifically impair the progeny of the apicoplast genes, resulting in their abnormal cell division.