Chronic bronchitis is divided into acute exacerbation phase and remission phase. The treatment during acute exacerbation mainly focuses on controlling infections, and administrating antitussive, expectorant, and asthma-relieving medications. To control infections, antibiotics are empirically selected based on the common pathogens in the area. If the pathogen can be cultured, an antibiotic sensitive to the organism can be chosen based on the test. Oral administration is generally sufficient. In severe cases, medication can be administered intravenously. Patients with asthma are given bronchodilators. During the remission phase, treatment involves quitting smoking, avoiding inhalation of harmful gases and other harmful particles, strengthening physical health, preventing colds, and for patients with repeated respiratory infections, vaccines or immunomodulators may be administered to enhance immunity.