Hemoptysis refers to coughing up blood from some part of the lungs. Blood coming from other places, such as your stomach, can look like it's coming from the lungs. It's important for your healthcare professional to find where the bleeding is coming from and figure out why you're coughing up blood.

In adults, some of the more common causes of coughing up blood include:

1. Bronchitis
2. Bronchiectasis, which leads to a buildup of mucus that can be streaked with blood and raise the risk of infection
3. Pneumonia

Other possible causes of coughing up blood include these conditions and diseases:

1. Bronchial neoplasm, which is a tumor that stems from the large airway in the lung.
2. COPD (chronic obstructive pulmonary disease) — a long-term lung disease that causes blocked airflow from the lungs.
3. Cystic fibrosis
4. Lung cancer
5. Mitral valve stenosis
6. Pulmonary embolism
7. Tuberculosis

A person also may cough up blood due to:

1. Chest injury.
2. Drug use, such as cocaine.
3. Foreign body, which is some type of object or matter that entered the body and shouldn't be there.
4. Granulomatosis with polyangiitis
5. Infection by parasites.

Your healthcare professional can look at your symptoms to come up with a diagnosis.