Coughing up blood - Coughing up blood (hemoptysis) involves coughing or spitting up blood mixed with mucus or spit. It can have many causes, most of which aren’t serious. Still, see a healthcare provider immediately if you cough up a lot of blood, have a cough that worsens or have additional symptoms like chest pain, blood in urine or stools, or fever. - What is coughing up blood (hemoptysis)? Coughing up blood involves coughing or spitting up blood or bloody mucus from your lower respiratory tr