The antibacterial drug clinical follow six principles, when the patient appears clinical symptoms, signs and laboratory tests, as soon as possible to clarify the pathogenic bacteria of infection, through the pathogenic bacteria to select sensitive antibiotics, the selection of antibiotics to consider the patient’s systemic condition, the concentration of the drug to reach the tissues and organs, as well as the drug may occur adverse reactions, and drug prices and other factors to choose a reasonable antibiotic. If an antibiotic is not effective, it can be combined with another antibiotic for treatment, which can reduce the dose of drugs, and can improve the efficacy and reduce the toxicity and adverse reactions of drugs, while some diseases can be prevented from applying antibiotics, such as after gastrointestinal thoracic and abdominal surgery can be prevented from applying antibiotics. Some patients with liver and kidney insufficiency or renal insufficiency must use reasonable and safe antibacterial drugs to prevent the unreasonable application of antibacterial drugs.