Why Is There Blood in My Mucus?

By Latifa deGraft-Johnson, MD
Medically reviewed checkmarkMedically reviewed
November 30, 2022

If you feel unwell and are struggling with a respiratory illness, you may cough up red mucus. Red phlegm or mucus is a sign that blood has been mixed in with your sputum.

This is a common occurrence in many mild respiratory illnesses including upper respiratory infections such as bronchitis or asthma. It can be alarming to see blood in your mucus, especially if there is a lot of it. In most cases, a small amount of blood in your mucus is nothing to worry about. Coughing up or vomiting large amounts of blood can be a sign that you have a more serious health condition that needs medical attention. 

In this article, I’ll help you understand where the blood in your mucus might be coming from, and what could have caused it. I’ll tell you how it’s treated, and when you should see a medical professional about blood in your mucus.

Where is the Blood in My Mucus Coming From?

Blood in the sputum typically comes from the lungs, but in some cases, it may also originate in other parts of the body, such as the stomach or digestive tract.

It can be brought on by a range of factors.

  • From the lungs (hemoptysis): Bright red, frothy blood that may be mixed with mucus is usually caused by persistent coughing or a lung infection. 
  • From the digestive tract (hematemesis): In less frequent circumstances, blood in the mucus can originate in the stomach or digestive tract. A clear indication of this is if you cough up dark blood that contains traces of food. Blood that comes from your stomach or digestive tract could be a symptom of a more serious health condition that requires medical attention. 

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Common Causes of Blood in Mucus

Common causes of blood in mucus include:

Prolonged Coughing 

Not only is a persistent cough frustrating, it can also be damaging to your respiratory tract. A severe cough can tear the blood vessels in your upper respiratory tract, resulting in blood in your mucus. 


There are a host of reasons why you might get a nosebleed. Common causes include nasal dryness, nose-picking, or injury.

This can lead to a loss of blood from the tissue that lines the inside of your nose.


Coughing up blood is a common symptom of chronic bronchitis.

This upper respiratory infection involves persistent or recurring inflammation of the airways. The inflammation causes persistent cough and the production of sputum.

Serious Causes of Blood in Mucus

Larger amounts of blood in your sputum, and coughing it up regularly, can be a warning of a more serious health condition. These include:


Pneumonia is caused by an inflammation of the lung tissue from a bacterial or viral infection.

The air sacs fill with pus and may become solid. People with pneumonia may cough up blood and experience chest pain when breathing or coughing.

They may also experience fatigue, fever, sweating, and chills


A contagious infection that usually targets your lungs, tuberculosis is caused by harmful bacteria that can spread from person to person in direct contact.

A person with tuberculosis will often experience symptoms such as a fever, sweating, chest pain, pain while breathing or coughing, and a persistent cough that can result in expelling red mucus. 

Pulmonary embolism 

A pulmonary embolism is a blood clot in one artery of a lung. It can cause chest pain (usually made worse by breathing), sudden shortness of breath, and coughing up blood.

Pulmonary aspiration 

This is a condition where a person accidentally inhales food, liquids, saliva, vomit, or an object into their windpipe and lungs. This can result in coughing, difficulty breathing, discomfort, and in some cases, choking.

The aggravation of the windpipe could damage the tissue lining which results in blood in the sputum. 

Pulmonary edema 

Pulmonary edema is a condition caused by excess fluid in the lungs. This makes it difficult to breathe.

It is most common in people with heart conditions. Symptoms include coughing up pink and frothy sputum, severe shortness of breath, and, for some, chest pain.

Lung cancer 

Lung cancer is a common side effect of prolonged cigarette smoking, particularly prevalent in smokers over age 40. Symptoms include a cough that does not go away, blood in the mucus, shortness of breath, chest pain, and sometimes bone pain or headaches.

Throat cancer 

Cancer in the throat, larynx, or windpipe can cause swelling or a sore that does not heal. If throat cancer spreads to the lungs, it may result in coughing up blood.

Cystic fibrosis 

An inherited, life-threatening disorder that attacks the lungs, digestive system, and other parts of the body, cystic fibrosis is an illness with no cure. This is often diagnosed in childhood.

Those who have cystic fibrosis often have shorter life spans and battle daily with the overproduction of mucus. Coughing up blood in mucus is a common occurrence for those with cystic fibrosis.  


Anticoagulants are blood-thinning medications that prevent blood clotting.

A side effect of taking anticoagulants is bleeding gums, which can cause you to cough up sputum that contains blood.

Diagnosing Why There is Blood is in Your Mucus

A healthcare provider will usually diagnose why blood is in your mucus by first reviewing your medical history and conducting a physical examination. During the examination, your doctor may ask you to cough, as well as check the nose and mouth for sites of bleeding. In some cases, additional tests may need to be done to determine the cause.

These include:

Chest X-rays 

If your doctor suspects that you have a more serious health condition that is causing you to cough up blood, they may request a chest X-ray. This test will show a clear image of your lungs and can detect lung cancer, infections, or air collecting in the space around a lung. 

CT scan 

CT scans use a combination of X-rays and computer technology to provide detailed images of any part of the body, including the bones, muscles, fat, organs, and blood vessels.

They can help doctors rule out more serious causes of coughing up blood. 


A bronchoscopy involves an endoscope (a camera at the end of a tube) being inserted into the airway through the nose or mouth. This can help your healthcare provider get a clearer idea of what is causing your symptoms.

Some can stop bleeding, and others can remove a blood clot.

Blood tests 

In some cases, your doctor may take samples of your blood or sputum for testing. This can help them detect viral or bacterial infections. 


A biopsy is a sample of tissue that is taken from the body for testing. Your doctor may require a biopsy to determine if the blood in your mucus is the result of a disease.

Treating Blood in Mucus

Treatments for stopping blood in mucus will vary depending on the underlying cause.

Possible treatments include:

  • Antibiotics: Antibiotics treat bacterial infections. Your doctor may prescribe antibiotics if you have pneumonia or tuberculosis.
  • Blood product transfusion: When coughing up blood is due to thin blood or coagulants, or if there are clotting problems, your doctor may suggest a blood product transfusion. 
  • Chemotherapy or radiotherapy: These treatments may be used to treat lung cancer.
  • Embolization: An embolization may be recommended if a major blood vessel is causing blood in the sputum. This process involves inserting a catheter into the vessel where bleeding is, and a metal coil, chemical, or fragment of gelatin sponge is used to seal it off.
  • Steroids: Steroids can help with inflammatory conditions that are causing bleeding.
  • Surgery: In rare cases, surgery may be carried out to remove a damaged or cancerous portion of the lung. This is usually only when bleeding is severe and/or persistent. 

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When to See a Medical Professional

If you are coughing up large amounts of blood frequently, speak to a medical professional.

Those who experience any of the following additional symptoms with blood in mucus should seek medical attention:

In the event you are coughing up dark blood that contains food particles, go to the hospital immediately.

This is usually a sign of a severe health problem in the digestive tract. 

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Frequently Asked Questions

Is blood in mucus serious?
Blood in mucus can be a sign of an upper respiratory infection. It may be the result of prolonged coughing, a nosebleed, or bronchitis. In some circumstances, blood in mucus is serious, especially if you are coughing up large amounts of blood, and the blood is dark or contains food particles. In this event, seek medical attention.
When should I be concerned about blood in my mucus?
If you cough up dark blood, especially if the blood contains food particles, this is a sign that the blood is coming from your stomach or digestive tract. Speak with a medical professional immediately.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Latifa deGraft-Johnson, MD

Dr. Latifa deGraft-Johnson is a board-certified family medicine physician with 20 years of experience. She received her bachelor's degree from St. Louis University, her medical degree from Ross University, and completed her family medicine residency at the University of Florida. Her passion is in preventative medicine and empowering her patients with knowledge.

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