Tequin is an antibiotic used to treat adults with lung, sinus, or urinary tract infections and also to treat certain sexually transmitted diseases caused by germs called bacteria. Sometimes viruses, rather than bacteria, may infect the lungs and sinuses (for example, the common cold). Tequin, like all other antibiotics, does not kill viruses.

The sexually transmitted disease called gonorrhea is treated by Tequin. Other sexually transmitted diseases including syphilis and non-gonococcal diseases are not treated by Tequin.