A Study to Explore If Long-term Use of Mucinex Can Help with Symptoms in Patients with Stable Chronic Bronchitis.

Inclusion Criteria:

• Adult patients with a diagnosis of SCB at recruitment, male and female, over 40years of age

• A Pulmonary Function Test with FEV1/FVC less than 0.7 (70%) at the time ofenrollment or at least a 10 year history of cigarette abuse.

• Patients who have chronic sputum production 3 months out of the year for 2consecutive years and a productive cough as part of their symptoms.

• Patients who understand and are able to fill out a questionnaire and ePRO weekly

• Patients who have not used guaifenesin containing products within one month of thetime of study enrollment

• Patients with 6 to 12 (ideally 12)-month historical data - retrieved from eitherelectronic medical records (EMR), electronic health records (EHRs), or provided bythe patient via interview.

Rescue medicine:

• No rescue medicine will be provided. Information regarding concurrent rescue medications, either OTC or via prescription, will be collected.

Exclusion Criteria:

• Patients who are pregnant or breastfeeding

• Participation in another study involving an investigational product within 30 daysof the baseline visit

• Pulmonary diagnosis other than CB, (such as cystic fibrosis, alpha-1 antitrypsindeficiency, bronchiectasis, or pulmonary fibrosis)

• Active lung cancer or history of lung cancer if it has been less than 2 years sincelung resection or other treatment including chemotherapy or radiation. If thepatient has a history of lung cancer, they must be in remission

• Psychiatric disorder that precludes participation in the study

• History of alcohol and/or drug abuse within one year of study start

• Patients taking intermittent antibiotics and patients taking oral and systemiccorticosteroids (e.g., prednisone at a dose of > 10 mg/day).

• Patients on a chronic stable dose of macrolide antibiotics at the start of the studymay be included at the discretion of the Principal Investigator.

• Patients who had an acute exacerbation of chronic bronchitis within a period of onemonth of starting the study that required systematic steroids or antibiotics

• Hypersensitivity to guaifenesin, or any other excipient listed in the product.