Norfloxacin is a fluoroquinolone antibacterial agent with broad-spectrum antibacterial effect, especially high antibacterial activity against aerobic gram-negative bacilli. It also has good antibacterial effect on penicillin-resistant Neisseria gonorrhoeae, Haemophilus influenzae and Catamorax. Norfloxacin is a bactericidal agent, which acts on the A subunit of bacterial DNA helicase to inhibit the synthesis and replication of DNA and cause bacterial death. It is mainly used for urinary tract infections, gonorrhea, prostatitis, intestinal infections, dermatological infections and typhoid and other Salmonella infections caused by sensitive bacteria. Norfloxacin is limited to simple lower urinary tract infections or intestinal infections. However, it should be noted that at present, more than half of the drug-resistant strains of Escherichia coli, the main causative agent of urinary tract infections in China, should be selected as far as possible with reference to the results of drug sensitivity tests. And it is no longer recommended for gonococcal infections.