1. Unstable patients who developed an exacerbation during the last 8 weeks

2. Patients who are current smokers or stopped less than 1 month

3. Patients who are allergic to acetylcysteine or to another element of the product

4. Patients with phenylketonuria or an untreated active peptic ulcer

5. Patients with any stage kidney and/or heart insufficiency or hypertension

6. Patients already treated with NAC for more than 6 months or during the last 3 months

7. Patients on continuous treatment with oral, inhalation, intravenous or intramuscular corticosteroids

8. Patients who are pregnant or are breast-feeding

9. Patients who are treated with orally administered cephalosporins

10. Patients using supplements containing antioxidants as vitamins C or E

Pilot Study to Assess the Effect of High Dose N-acetylcysteine (NAC) in Chronic Obstructive Pulmonary Disease (COPD) Patients