Azithromycin and levofloxacin are different in terms of category, mechanism of action, indications, adverse effects, contraindications, and so on. 1. Category: both belong to antibiotics, but different categories. Azithromycin belongs to macrolide antibiotics and levofloxacin belongs to quinolone antibiotics. 2. Mechanism of action: Azithromycin mainly exerts antibacterial effect by inhibiting bacterial protein synthesis. Levofloxacin can inhibit topoisomerase IV and other infectious bacterial DNA replication and produce bactericidal effect. 3. Indications: Azithromycin can be used for skin infections, upper and lower respiratory tract infections caused by gram-positive and gram-negative bacteria, and can also be used for pneumonia caused by mycoplasma. Levofloxacin has a wide antibacterial spectrum and can be used for genitourinary infections, respiratory system and intestinal infections. 4. Adverse reactions: azithromycin adverse reactions are mild, mainly abdominal pain, nausea, vomiting, rash and so on. Levofloxacin mainly has gastrointestinal reactions such as stomach discomfort, central nervous system reactions such as insomnia and headache, cardiotoxicity, cartilage damage, etc. 5. Contraindications: Azithromycin is contraindicated in those who are allergic to macrolides, and also contraindicated in those with severe hepatic and renal insufficiency. Levofloxacin is contraindicated in quinolone-allergic patients, pregnant and lactating women, and should also be used with caution in children, diabetic patients, and those with a history of psychiatric disorders. Azithromycin and Levofloxacin are both commonly used antibiotics, it is recommended to choose and use the drugs reasonably under the guidance of a physician after consultation.