Flema

Flema, also known as phlegm or sputum, is mucus produced by the airways. It is expelled by coughing and cleared from the respiratory tract. Flema is produced by goblet cells and submucosal glands in the trachea and bronchi and serves to trap inhaled particles and microbes; its components include water, mucin glycoproteins, immune cells, and microorganisms such as bacteria or viruses.

The color and texture can vary: clear or white flema is common, while yellow or green flema may reflect an immune response or infection. Brown or black flema can indicate smoke or pollution exposure, and blood-tinged flema is a red flag. Common causes include viral upper respiratory infections, bronchitis, pneumonia, asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, allergies, and exposure to irritants such as tobacco smoke.

If flema persists beyond several weeks, or is accompanied by high fever, chest pain, shortness of breath, coughing up blood, or significant weight loss, seek medical attention. Diagnosis may involve medical history, physical examination, and tests such as chest imaging or sputum analysis. Treatment depends on the underlying cause and may include fluids, rest, humidified air, and strategies to loosen mucus; antibiotics if a bacterial infection is suspected or confirmed; and inhalers or other therapies for asthma or COPD. Reducing exposure to irritants and stopping smoking can also help improve long-term symptoms.