Clarithromycin is a common antimicrobial drug to treat respiratory tract infections, skin and soft tissue infections, odontogenic infections, etc. It is not scary to follow the doctor’s instructions for regular application. Clarithromycin is mainly used to treat infections caused by pathogenic bacteria that are sensitive to it. Common diseases include upper respiratory tract infections (sinusitis, pharyngitis, etc.), lower respiratory tract infections (pneumonia, bronchitis, etc.), skin and soft-tissue infections (dandruff, cellulitis, folliculitis, etc.), infections of the genitourinary tract, and infections of odontogenic origin. It can be used to eradicate Helicobacter pylori in the presence of a gastric acid inhibitor. It can also be used to treat localized or diffuse infections caused by Mycobacterium avium, Mycobacterium intracellulare, or Mycobacterium intracellulare. It is also indicated for the prevention of mixed infections caused by diffuse Mycobacterium avium in HIV patients with CD4 lymphocyte counts ≤100/mm3. Adverse reactions to clarithromycin include abdominal pain, headache, diarrhea, dyspepsia, flatulence, nausea, vomiting, rash, taste reversal, acute hypersensitivity reactions, QT prolongation, hepatotoxicity, exacerbation of myasthenia gravis, and Clostridium difficile-associated diarrhea. This product is contraindicated in patients who are allergic to any of the macrolide antibacterial drugs, in patients with cardiac arrhythmia, cholestatic jaundice, abnormal liver function, and in patients taking colchicine, ergot alkaloids, HMG-CoA reductase inhibitors. It is recommended that patients who feel unwell should go to regular hospitals in time and follow the doctor’s instructions for symptomatic treatment.