Haemoptysis is the medical term for coughing up blood. It can be a frightening experience, but it's important to remember that haemoptysis is not always a sign of a serious underlying condition. In most cases, haemoptysis is caused by a minor infection or irritation of the lungs and will resolve on its own with time. However, if you are experiencing haemoptysis, it's important to see a doctor so they can rule out any potentially more serious causes.