It has been deduced that reducing the production of mucus or improving the clearance of sputum in the airway is the key to enhance the therapeutic efficacy for bronchiectasis . Mucoactive drugs are commonly used to clear the airway in mucus hypersecretion diseases. Currently, investigators have found that N-acetylcysteine (NAC), an effective mucolytic agent, not only reduces the viscosity and elasticity of sputum, but it also has anti-inflammatory and antioxidant activity.

Additionally, the Spanish guidelines on the treatment of bronchiectasis indicate that the use of N-acetylcysteine should be considered for patients with bronchiectasis and COPD. Therefore, as a classic mucolytic agent with antioxidant and anti-inflammatory properties, N-acetylcysteine can be effective in the treatment of bronchiectasis

Inclusion Criteria:

• Subjects aged above 18 years old; with a diagnosis of bronchiectasis who are admitted to chest department due to acute exacerbation

Exclusion Criteria:

• current smokers, a known allergy to N-acetylcysteine; pregnancy or lactation (for women); primary diagnosis of COPD or asthma