Hemoptysis is when you cough up blood from your lungs. It can be a sign of a serious medical condition. Infections, cancer, and problems in blood vessels in your lungs can cause it.

Coughing up blood, medically known as hemoptysis, involves coughing or spitting up blood or blood-streaked mucus from your respiratory tract (i.e. lungs and airways). Coughed-up blood may appear ...