Doxycycline is used to treat bacterial infections such as pneumonia and other respiratory tract infections, as well as infections of the skin and eyes, infections of the lymphatic, intestinal, genital, and urinary systems, and infections spread by ticks, lice, mites, infected animals, and contaminated food and water. Its also used to treat acne in combination with other drugs. Doxycycline is also used to treat or prevent anthrax (a dangerous infection that can be distributed on purpose as part of a bioterror assault), as well as to treat plague and tuleramia in patients who have been exposed to anthrax in the air (serious infections that may be spread on purpose as part of a bioterror attack). Its also used to keep malaria at bay. Doxycycline can also be used to treat food poisoning in those who cannot be treated with penicillin.