Coughing up blood can be caused by a variety of lung conditions. The blood may be bright red or pink and frothy, or it may be mixed with mucus.

Also known as hemoptysis (he-MOP-tih-sis), coughing up blood, even in small amounts, can be alarming. However, producing a little blood-tinged sputum isn't uncommon and usually isn't serious.

Call 911 or seek emergency care if you're coughing up blood in large quantities or at frequent intervals.

Hemoptysis refers to coughing up blood from some part of the lungs (respiratory tract). Blood coming from elsewhere, such as your stomach, can appear to be from the lungs. It's important for your doctor to determine the site of the bleeding, and then determine why you're coughing up blood.

The major cause of coughing up blood is chronic bronchitis or bronchiectasis. Other possible causes of coughing up blood include:

• COPD (chronic obstructive pulmonary disease) — the blanket term for a group of diseases that block airflow from the lungs — including emphysema.
• Cystic fibrosis
• Drug use, such as crack cocaine
• Foreign body
• Granulomatosis with polyangiitis
• Lung abscess
• Lung cancer
• Mitral valve stenosis
• Parasitic infection
• Pneumonia — an infection in one or both lungs.
• Pulmonary embolism — a blood clot in an artery in the lung.
• Trauma to the chest
• Tuberculosis

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

Call your doctor if you're coughing up blood. He or she can determine whether the cause is minor or potentially more serious. Call 911 or emergency medical help if you're coughing up a lot of blood or if the bleeding won't stop.