Tetracycline is an antibiotic that fights bacterial infections. It is a broad-spectrum antibiotic that can treat a wide variety of infections, including:

• Infections caused by bacteria, such as pneumonia, respiratory tract infections, skin infections, eye infections, lymphatic infections, intestinal infections, genital infections, and urinary tract infections.
• Infections spread by ticks, lice, mites, and infected animals.
• Acne.
• Plague and tularemia (serious infections that may be spread on purpose as part of a bioterror attack).
• Certain types of food poisoning and anthrax (a serious infection that may be spread on purpose as part of a bioterror attack).
• Lyme disease and malaria.
• Certain types of stomach ulcers when used in combination with anti-ulcer medications.

Tetracycline is also used off-label to treat other conditions such as rosacea, bullous dermatoses, sarcoidosis, Kaposi sarcoma, pyoderma gangrenosum, hidradenitis suppurativa, Sweet syndrome, a1-antitrypsin deficiency, panniculitis, pityriasis lichenoides chronica, rheumatoid arthritis, scleroderma, cancer, and cardiovascular diseases (abdominal aortic aneurysm and acute myocardial infarction).

It is important to note that tetracycline should only be used to treat bacterial infections and not viral infections such as the flu or common cold. Using antibiotics when they are not needed can cause them to not work for future infections and increase the risk of developing antibiotic-resistant infections.