Gemifloxacin mesylate, sold under the brand name Factive among others, is a broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia.

[citation needed] Gemifloxacin is indicated for the treatment of infections caused by susceptible strains of the designated microorganisms in the conditions listed below.

MDRSP includes isolates previously known as PRSP (penicillin-resistant Streptococcus pneumoniae), and are strains resistant to two or more of the following antibiotics: penicillin, 2nd generation cephalosporins, e.g., cefuroxime, macrolides, tetracyclines and trimethoprim/sulfamethoxazole.

[3][4] Some of the serious adverse effects which occur more commonly with fluoroquinolones than with other antibiotic drug classes include CNS and tendon toxicity.

A study showed that gemifloxacin possess anti-metastatic activities against breast cancer in vitro and in vivo (in mice).