- Community-acquired pneumonia
- Chronic cor pulmonale
- Chronic bronchitis
- Chronic Obstructive Pulmonary Disease
- Child cough
- Central lung cancer
- Bronchitis
- Bronchiolitis
- Bronchiectasis
- Atypical pneumonia
- Atelectasis
- Asthmatic bronchitis
- Allergic cough
- Air conditioning sickness
- Adenovirus pneumonia
- Acute upper respiratory tract infection