The aim of this study is to assess the effectiveness in preventing exacerbation of 52 weeks lysozyme administration in patients with COPD.

Inclusion criteria;

• Patients were eligible for inclusion in the study if they were over 20 years of age and below 85 years of age, and had a smoking history, a diagnosis of COPD, a ratio of FEV1 to forced vital capacity(FVC) of less than 70%, and a documented history of at least one exacerbation leading to any treatment within the previous year.

Exclusion criteria;

• Patients with egg allergy
• Patients with domiciliary oxygen therapy
• Patients with pneumonia or pulmonary tuberculosis
• Patients with severe cardiovascular disorder,severe kidney disorder, severe hepatic disorder, severe hematological disorder.
• Patients with cancer.