What should you know about coughing up red mucus?

Red streaks can follow irritated airways, a forceful cough, a cold, or acute bronchitis. Blood may also come from the nose, gums, or throat and be noticed while coughing. Ongoing cough with repeated blood-stained sputum can occur with conditions such as bronchiectasis, asthma, or chronic cough, but the colour cannot establish a diagnosis. A clinician may also consider medicines, smoking or vaping exposure, infection, and other chest causes.

Describe whether the blood is bright red, mixed through mucus, clotted, or separate from it. Record how often it happens and whether you also have fever, chest pain, dizziness, or shortness of breath.

Contact a healthcare professional for advice rather than relying on colour changes alone. Keep a sample or photograph if safe and practical, and bring a list of medicines, including blood thinners. Avoid smoking, vaping, and strenuous activity until you have guidance. Do not use someone else’s antibiotics. Assessment may include a chest examination, oxygen check, and tests chosen according to the amount of blood and your other symptoms.

Call emergency services immediately if you are coughing up a large amount of blood, bleeding repeatedly, struggling to breathe, choking, fainting, confused, or developing blue or grey lips. Chest pain, a fast or irregular heartbeat, severe weakness, or sudden deterioration also require urgent help. Do not drive yourself if you feel faint or breathless. Even a small amount needs prompt clinical advice when you take anticoagulants, have a clotting disorder, or have a significant lung condition.

Ask: Could the blood be from my upper airway rather than my chest? What might explain the amount and pattern I described? Do any of my medicines increase bleeding? Do I need an oxygen check, chest imaging, or other tests? Which symptoms mean I should call emergency services?