Sputum: Characteristics, Causes, Prevention

Sputum is mucus that is produced in the lungs and respiratory tract. It is important to prevent microbes from entering the airways and lungs. Usually, it is transparent and thin, completely invisible. However, when an infection appears, the mucus can thicken and change color. Therefore, depending on the disease, the mucus of different colors may form.

Sputum_ Characteristics, Causes, Prevention

What causes sputum?

Green or yellow sputum

This is usually a sign that the body is fighting infection. The color comes from white blood cells. Change occurs with the severity and duration of a possible disease.

Green or yellow sputum is usually caused by:

  • Bronchitis: usually begins with a dry cough and over time, green or yellow forms with clear or white sputum.
  • Pneumonia: this is usually a complication of another respiratory disease. Symptoms depend on the type of pneumonia. Cough, fever, chills, and shortness of breath are common symptoms in all types of pneumonia.
  • Sinusitis: also known as sinus infection. This virus may cause another virus, allergy, or bacteria.
  • Cystic fibrosis: a chronic disease of the lungs when mucus accumulates in them.

Brown sputum

Brown sputum often means old blood. This color is usually caused by:

  • Bacterial pneumonia;
  • Bacterial bronchitis: the risk of developing chronic bronchitis is increased if you smoke or often inhale different fumes and other irritants.
  • Cystic fibrosis;
  • Pneumoconiosis: inhalation of various dust, such as coal, asbestos and silicosis, can cause this incurable lung disease;
  • Pulmonary abscess: This is a cavity filled with pus inside the lungs. It is usually surrounded by infected and inflamed tissue.

White sputum

White sputum is usually caused by:

  • Viral bronchitis;
  • GERD: this chronic condition affects the digestive system;
  • COPD: this condition leads to a narrowing of the airways, and the lungs to an excess of mucus;
  • Congestive heart failure: This occurs when the heart does not pump enough blood to other parts of the body. Fluid builds up in various areas, leading to edema. Fluid builds up in the lungs and can lead to an increase in white sputum.

Black sputum

Black sputum is also called melanoptis. The appearance of black sputum may mean that a large amount of something black, like coal dust, was inhaled. It may also mean that there is a fungal infection. Black sputum is usually caused by:

  • Smoking: smoking cigarettes or other drugs can cause sputum;
  • Pneumoconiosis;
  • Fungal infection: Black yeast called Exophiala dermatitidis causes this infection. They often affect people with cystic fibrosis.

Clear sputum

Clear sputum is usually caused by:

  • Allergic rhinitis: also called nasal allergy or sometimes hay fever;
  • Viral bronchitis: in some cases, you may find that sputum progresses to yellow or green;
  • Viral pneumonia.

Bloody sputum

Red or pink sputum is usually caused by:

  • Pneumonia: this lung infection can cause red sputum as it progresses. It may be accompanied by chills, fever, chest pain;
  • Tuberculosis: the main symptoms are coughing for more than three weeks, coughing up blood and red sputum, fever and night sweats;
  • Congestive heart failure, in addition to a pink or red tinge of sputum, you can feel shortness of breath;
  • Pulmonary embolism: This condition is life-threatening and can also cause shortness of breath and chest pain;
  • Lung cancer: this condition causes many respiratory symptoms: coughing with red sputum or even blood.


A doctor may perform a variety of tests to determine the cause, including radiography and sputum analysis. Sputum can be analyzed in the laboratory to determine its content and to determine infection or cancer. Tests may include:

  • Sputum culture: Sputum culture is done by placing a sputum sample in a growing medium (dishes with agar) and looking for growth. This can be done to determine the specific type of bacteria that causes pneumonia;
  • Sputum for detecting tuberculosis: A sputum sample may be obtained to search for tuberculosis;
  • Sputum cytology: In sputum cytology, a sputum sample is examined under a microscope. This can be done to look for signs of tuberculosis or signs of cancer cells. At one time, it was believed that sputum cytology can detect lung cancer but this is not an effective screening tool.

Diseases accompanied by sputum

Some conditions that cause an increase in sputum include:

  • chronical bronchitis;
  • bronchiectasis;
  • pulmonary edema;
  • congestive heart failure;
  • pulmonary embolism;
  • tuberculosis;
  • obstructive pulmonary disease;
  • allergy;
  • cystic fibrosis,
  • pneumoconiosis;
  • fungal infection.

What doctor to contact?

Sputum production is part of the respiratory system. However, it threatens health if it begins to affect normal daily life. A patient should contact a family doctor to make a correct diagnosis and begin treatment. It is important to remember that doctors cannot diagnose a specific disease based on sputum color. More detailed analysis is required.


You can use these methods of prevention of lung diseases and sputum production:

  • Give up smoking. Smoking damages the lungs and increases the risk for a number of diseases. This is because when materials are burned, harmful substances are released into the lungs (toxins and carcinogens). If you still smoke, it’s never too late to quit. Also, stay away from extraneous smoke, residual tobacco vapors adjacent to walls and furniture, which (together with pollutants in the room) form damaging compounds;
  • Daily hygiene. Wash your hands thoroughly with soap and water several times a day to prevent germs from entering the body;
  • Protection. To help stop the spread of germs, cover your mouth and nose with a cloth or gauze bandage when you cough or sneeze. Stay away from the crowds during the peak season of colds and flu. Relax, eat right and keep your stress levels under control;
  • House cleaning. Air fresheners, molds, pet dander, and building materials are potential problems. When cooking, turn on the fan and avoid using aerosol products such as a hair spray. Change your air filter. Poor ventilation, closed work areas and increased heat are also responsible for the disease. Avoid breathing toxic fumes from chemicals, solvents, and paints. Wear protective masks when handling chemicals and report hazardous working conditions;
  • Regular examination. Be sure to consult a doctor if you notice shortness of breath, pain during breathing, dizziness, persistent cough, wheezing, cough during physical exertion, pain in the respiratory tract. Do fluorography regularly (maximum 1 time per year);
  • Physical activity. Do sports or physical activity daily for 30 minutes to lighten your lungs and increase your oxygen transport and metabolism. People with lung diseases such as asthma and COPD should pay special attention to the level of air pollution.

Category: Health Care

Tags: lung disease, lungs, Respiratory diseases, respiratory system, sputum