Coughing up blood: what should you know?

A hard cough can irritate the nose, throat, or airway and leave a small streak in mucus. Blood may also accompany acute bronchitis or a longer-term airway condition such as bronchiectasis. The appearance can be bright red, pink, or mixed with phlegm, but colour alone cannot explain the cause. Blood from the mouth or stomach can sometimes be mistaken for blood from the lungs.

A clinician will ask how much you saw, whether it happened once or repeatedly, and whether you have fever, breathlessness, chest pain, leg swelling, weight loss, or a history of lung disease. Bring a photo or sample description if safe to do so.

Stop smoking, avoid strenuous activity until advised, and note the amount and frequency. Do not suppress a significant bloody cough with someone else’s medicine. Tell the clinician about blood-thinning medicines, recent illness, nosebleeds, and any injury. Even a small unexplained episode deserves prompt medical advice, particularly if it returns.

Call emergency services for heavy or ongoing bleeding, severe shortness of breath, chest or upper-back pain, a very fast heartbeat, fainting, confusion, or blue lips. Seek same-day care for repeated streaks, fever, worsening cough, marked weakness, or new breathlessness. Do not drive yourself if you feel faint or are struggling to breathe.

Ask where the blood is most likely coming from, whether your medicines could contribute, and which examination or imaging is needed. Confirm what amount or symptom should send you straight to emergency care and how to manage your cough while the cause is being checked.