or green in appearance. Coughing up blood can occur in small or large amounts. In most cases, the amount of blood coughed up is minimal. You may cough up blood-streaked mucus or large amounts of ...

Ogun says. So it’s not out of the ordinary to cough up mucus from time to time. But if the mucus is thick or a different color (green or yellow), it could be a sign of pneumonia or bronchitis.