Sputum, or phlegm, is a mixture of saliva and mucus that you’ve coughed up. Sometimes sputum can have visible streaks of blood in it. The blood comes from somewhere along your body’s respiratory tract.

The respiratory tract includes the:

  • mouth
  • throat
  • nose
  • lungs
  • passageways leading to the lungs

Sometimes blood-tinged sputum is a symptom of a serious medical condition. But blood-tinged sputum is a relatively common occurrence and isn’t typically cause for immediate concern.

If you’re coughing up blood with little or no sputum, seek immediate medical attention.

Common causes of blood-tinged sputum include:

More serious causes of blood-tinged sputum can include:

Lower respiratory infections and inhaling a foreign object are the likely causes of blood-tinged sputum in children.

Call a doctor or seek medical attention right away if you experience any of these symptoms:

These symptoms are associated with serious medical conditions.

When you see a doctor about the blood-tinged sputum, they’ll first ask you if there was any noticeable cause, like:

They’ll also want to know:

  • how long you’ve had blood-tinged sputum
  • how many times you cough it up during the day
  • how the sputum looks
  • the amount of blood in the sputum

Your doctor will listen to your lungs while you breathe and may look for other concerning symptoms, like a rapid heart rate, wheezing, or crackles. They’ll also ask about your medical history.

Your doctor may also use one or more imaging studies or procedures to help them reach a diagnosis.

  • Chest X-rays can be used to diagnose a variety of different conditions. A chest X-ray is often one of the first imaging studies they order.
  • A CT scan of the chest can provide a clearer image of soft tissues for evaluation.
  • During a bronchoscopy, your doctor lowers a bronchoscope down the back of the throat and into the bronchi. This instrument helps them check for obstructions or abnormalities in your airways.
  • They can order blood tests to diagnose different conditions, as well as determine how thin your blood is and check to see if you’ve lost so much blood that you’ve developed anemia.
  • If your doctor notices a structural abnormality in your lungs, they may order a biopsy. During a biopsy, a sample of tissue is removed from your lungs and sent to a lab for evaluation.

Treating blood-tinged sputum will require treating the underlying condition that’s causing it. In some cases, treatment can also involve reducing inflammation or other related symptoms.

Treatments for blood-tinged sputum can include:

  • oral antibiotics for infections like bacterial pneumonia
  • antiviral medications, like oseltamivir (Tamiflu), to reduce the duration or severity of a viral infection
  • cough suppressants for a prolonged cough
  • drinking more water, which can help flush out remaining sputum
  • surgery to treat a tumor or blood clot in the lung

For people who’re coughing up large amounts of blood, treatment focuses first on stopping the bleeding and preventing aspiration, which occurs when you breathe foreign material into your lungs. Then treatment focuses on addressing the underlying cause.

Call your doctor before using any cough suppressants, even if you know the underlying cause of your symptoms. Cough suppressants can lead to airway obstructions or keep the sputum trapped in your lungs, prolonging or worsening an infection.

Blood-tinged sputum can sometimes be a symptom of an underlying condition that you can’t prevent. But methods may be available to help prevent some cases of blood-tinged sputum.

The first line of prevention is to take steps to avoid the respiratory infections most likely to bring on this symptom.

You can do the following to prevent blood-tinged sputum:

  • Consider cutting down on smoking, if you smoke. Smoking causes irritation and inflammation. It also increases the likelihood of serious medical conditions.
  • Drink more water, if you feel a respiratory infection coming on. Drinking water can thin out sputum and help flush it out.
  • Keep your house clean. Dust is easy to breathe in, and it can irritate your lungs and make your symptoms worse if you have COPD, asthma, or a lung infection. Mildew and mold can also cause respiratory infections and irritation, which can lead to blood-tinged sputum.
  • See your doctor if you have yellow or green sputum. Coughing up yellow or green sputum may be a sign of a respiratory infection. See your doctor for treatment early on to help prevent complications or worsening of symptoms later.