What Causes Black Mucus and Phlegm?

Medically reviewed by Sanja Jelic, MD

Black mucus is a dark-colored substance (also called "phlegm") expelled from your nose and mouth. It is rare to have black mucus, and it may signal a serious underlying condition, such as tuberculosis or cancer. Your mucus can also become dark if you've been exposed to extreme air pollution. If you have developed black mucus, it's best to contact a healthcare provider.

This article will discuss more about what causes black mucus and how you can treat these conditions.

Related:What Is Mucus?

Black mucus is typically the symptom of an overarching condition that usually comes with other symptoms like a cough, fever, shortness of breath, or other respiratory problems.

Black Mucus Causes

Black mucus may also be called melanoptysis and is commonly found in coal workers who inhale black dust all day. Certain conditions are also associated with black mucus.

Coal Workers’ Pneumoconiosis (Anthracosis)

A type of pneumonia known as black lung is commonly found in coal miners. When inhaled, coal dust enters the tissues of the lungs. Over time, these deposits form masses and scar tissue. The black mucus expelled with coughing results from infections and destruction caused by this process.

Tuberculosis

Tuberculosis is a bacterial infection that affects the lungs. It can cause permanent lung damage and appear with symptoms like a cough that produces blood or mucus. Other symptoms include chest pain and difficulty breathing.

Cancer

When cancer occurs in the lungs, it creates masses and destroys healthy tissue. Bronchopulmonary melanoma is a type of cancer that affects the lungs and is known for producing dark or black mucus.

Necrosis

Tissue damaged or destroyed by disease, infection or lack of oxygen turns dark or black as it enters a state of necrosis (tissue death). Coughing can bring up bits of this necrotic (dead) tissue, giving your mucus a dark or stained appearance.

Fungal Infections

Many types of infections cause mucus production, but some are known more than others for producing darker-colored sputum. One of these is Exophiala dermatitidis, a black yeast infection that is common in people with cystic fibrosis.

Another is Aspergillus niger, a type of fungal infection that can be caused by inhaling black mold spores. People with a weakened immune system are at a higher risk for developing allergic reactions and lung and other organ infections from inhaling aspergillus mold spores.

Finally, mucormycosis is a rare fungal infection that causes black mucus and can lead to dark or black lesions on other body areas.

Substance Use

Using substances like cigarettes can cause black mucus from smoke particles and other debris that collects in the lung tissues. Coughing up black mucus is also strongly associated with chronic cocaine-induced pulmonary injury.

Pollution

People who live in areas with dense air pollution or who work in certain industries may cough up dark black mucus. Like coal miners, people who live in highly polluted areas breathe in particles that can collect in the lung tissue and appear in mucus after a cough.

Breathing in smoke from a large fire can also make your mucus appear darker due to the particles in the smoke.

How Is Black Mucus Treated?

You may require antibiotics or antifungal medications if bacteria or fungi has caused your black mucus. Other causes of black mucus, like coal workers’ pneumoconiosis (anthracosis), are not as easily treated.

Black mucus caused by severe disease or lung necrosis can result in tissue damage that cannot be reversed. Treatment instead focuses on oxygen supplementation and symptom relief.

Examples of treatments for severe lung disease include:

• Medications such as steroids, to reduce inflammation of the airways

• Pulmonary rehabilitation to help strengthen the muscles that help you breathe

• Supplemental oxygen to ensure your body is getting enough oxygen

Related:An Overview of Obstructive vs. Restrictive Lung Diseases

Complications of Black Mucus

Exposure to pollution, irritants, or mold spores that you could inhale increases your risk for diseases that produce black mucus.

Some complications of diseases like black lung include:

• Heart failure

• Lung cancers

• Respiratory failure

Related:Lung Cancer Complications

Related:What to Expect From a Spirometry Test

When to See a Healthcare Provider

Anytime you develop a cough that doesn't resolve within a few weeks, it's a good idea to see a healthcare provider to rule out serious diseases or infections. Mucus production is typical in many disorders, but black mucus can signal more severe illness. Seek medical care if your mucus appears black.

If you experience shortness of breath, chest pain, or a bluish tone to your lips or skin, seek medical attention immediately.

Learn More:What Is a Pulmonologist?

Summary

Mucus is a mixture of fluids and bits of tissues expelled with a cough or when you blow your nose. There are many colors of mucus, but black mucus often signals severe disease or infection. Talk to your healthcare provider about your medical history and your risk factors for conditions like fungal infections, tuberculosis, or even black lung disease.

Here's what other mucus colors reveal about your health:

• Clear: Allergies or early stage of virus

• White: A cold or other infection

• Yellow: You are in the beginning stages of illness and your body is fighting a virus

• Green: You likely feel very sick and your body is fighting a virus

• Pink or red: Blood is in your nose from pregnancy, dryness, or injury

• Brown: There is a dried blood in your mucus