Levofloxacin Hydrochloride is a third-generation quinolone drug. Quinolones target bacterial deoxyribonucleic acid (DNA), impede DNA gyrase, and cause irreversible damage to bacterial DNA to achieve antibacterial effect. Levofloxacin, as a third-generation quinolone, has been improved on the basis of the first and second generations, so that its antibacterial effect not only on gram-negative bacteria is further strengthened, but also on gram-positive bacteria, such as staphylococci, with a certain degree of resistance. Therefore, at present, levofloxacin can be applied not only to infections of the genitourinary system and respiratory tract, but also to gastrointestinal infections, typhoid fever, bone and joint infections, skin and soft tissue infections, sepsis and other systemic infections. Besides, it can also be applied to the treatment of chronic bronchitis.