Coughing up phlegm is a natural process that helps the body clear the airways of mucus, irritants, and harmful particles. However, when this condition becomes persistent or when the phlegm changes in colour or consistency, it may indicate an underlying health issue that requires medical attention. Healthcare professionals often stress that recognising these warning signs early can lead to faster diagnosis and more targeted treatment.

Phlegm plays a protective role by trapping bacteria, viruses, and dust, preventing them from reaching the lungs. While occasional mucus production is normal, excessive or discoloured phlegm may point to infections or chronic respiratory conditions. Understanding these changes helps individuals make informed decisions about their health.

What Your Phlegm Colour Can Reveal

• Clear or white phlegm usually indicates mild conditions such as viral infections, allergies, or minor airway irritation, often improving with rest and hydration
• Yellow, green, or brown phlegm may suggest bacterial infections, bronchitis, or sinus issues that require prompt medical evaluation to avoid complications

Doctors often rely on phlegm colour as an initial diagnostic indicator to determine the nature of the illness. It helps differentiate between viral and bacterial infections, guiding appropriate treatment methods.

Common Causes of Persistent Cough With Phlegm

• Chronic bronchitis, asthma, postnasal drip, and gastroesophageal reflux disease (GERD) are frequent causes of prolonged cough with mucus
• Environmental factors such as smoking, pollution exposure, or nearby construction can also contribute to ongoing respiratory irritation

A cough lasting more than three weeks is considered persistent and should not be ignored. It may affect daily life and indicate deeper respiratory concerns that need