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Tuberculosis (TB)

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Tuberculosis (TB)

Condition Basics

What is tuberculosis (TB)?

Tuberculosis (TB) is a serious disease caused by a type of bacteria that is spread through the air. TB is easily spread from person to person through coughs or sneezes. TB usually occurs in the lungs. But it can spread to other parts of the body.

TB is either active or latent.

  • Active TB means that the TB bacteria are growing and causing symptoms. If your lungs are infected with active TB, it's easy to spread the disease to others.
  • Latent TB means that you have the TB bacteria in your body, but your body's defenses (immune system) are keeping it from turning into active TB. This means that you don't have any symptoms of TB right now and can't spread the disease to others. If you have latent TB, it can become active TB.

What causes it?

TB is caused by Mycobacterium tuberculosis. This is a type of slow-growing bacteria. It thrives in parts of the body that are rich in blood and oxygen, such as the lungs.

What are the symptoms?

People with latent TB don't have symptoms. Symptoms of active TB may include a cough that brings up a thick mucus, tiredness, weight loss, fever, a fast heartbeat, or swelling in the neck. In rare cases, you may have shortness of breath and chest pain.

How is it diagnosed?

A skin or blood test is used to check for TB. To find TB in the lungs, doctors may test lung mucus or do a chest X-ray. To find TB that's not in the lungs, doctors may check a tissue sample (biopsy) or do imaging tests.

How is TB treated?

TB is treated with antibiotics to kill the TB bacteria. How many antibiotics are used and how long you'll take them may depend on whether you have active or latent TB. TB can only be cured if you take all the doses of your medicine.

How It Spreads

TB that's in the lungs can spread when a person who has active TB breathes out air that has the TB bacteria in it. Another person may breathe in the bacteria. Things like coughing can also release even more bacteria. TB that isn't in the lungs can't spread easily to others.

What Increases Your Risk

Some people are more likely than others to get TB. This includes people who have a weak immune system, have close contact with someone who has active TB, have poor access to health care, or abuse drugs or alcohol. People who travel or live where untreated TB is common are also at risk.

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TB in the lungs is spread very easily. To avoid getting TB:

  • Don't spend long periods of time in a stuffy, closed room with someone who has active TB until that person has been treated for at least 2 weeks.
  • Use measures to protect yourself, if you work somewhere that cares for people who have untreated TB. An example is wearing a face mask. Face masks must be certified by the CDC and National Institute for Occupational Safety and Health (NIOSH).
  • If you live with someone who has active TB, help the person follow treatment instructions.

The TB vaccine

A TB vaccine is used in parts of the world where the risk of getting TB is higher. But it's almost never used in the United States.


If you have latent TB, you won't have symptoms. If the disease becomes active TB, you will most likely have symptoms.

Symptoms of active TB in the lungs include:

  • A cough with thick, cloudy, and sometimes bloody mucus from the lungs (sputum) for more than 2 weeks.
  • Fever, chills, and night sweats.
  • Fatigue and weakness.
  • A rapid heartbeat.
  • Loss of appetite and losing weight without trying.
  • Shortness of breath and chest pain.

These symptoms start gradually and develop over weeks or months. You may have one or two mild symptoms and not know that you have the disease.

Symptoms of TB outside the lungs vary widely, depending on which part of the body is infected. For example, back pain can be a symptom of TB in the spine. Or your neck may get swollen when lymph nodes in the neck are infected.

Other conditions with symptoms similar to TB include pneumonia and lung cancer.

What Happens

TB develops when you breathe TB bacteria into your lungs. The infection usually stays in the lungs. But the bacteria can move through the bloodstream to other parts of the body.

In a person who has a healthy immune system, the body usually fights the infection by walling off the bacteria into tiny capsules. (These are called tubercles.) This stage is called latent TB, and most people never go past it.

If a person's immune system can't stop the bacteria from growing, the TB becomes active. Of people who have latent TB, 5% to 10% (1 to 2 people out of 20) will develop active TB at some point in their lives.footnote 1

If the TB is active in the lungs, skipping doses of medicine can delay a cure and cause a relapse.

Without treatment, active TB can cause other serious health problems, such as respiratory damage.

When to Call a Doctor

Call your doctor now if you:

  • Have symptoms (such as a cough that may produce bloody mucus along with fever, fatigue, and weight loss) that could be caused by tuberculosis (TB).
  • Were in close contact with someone who has untreated active TB, which can be spread to others, or you've had lengthy close contact with someone you think has untreated active TB.
  • Have blurred vision or changes in how you see colors and are taking ethambutol for TB.
  • Notice yellowing of your skin and the whites of your eyes (jaundice), or you have belly pain and you are taking isoniazid or other medicines for TB.

Follow up with your doctor if you:

  • Recently had a TB skin test. You need to have a skin reaction measured by a health professional within 2 to 3 days after the test. This measurement is important in deciding whether you need more tests or treatment.

Exams and Tests

Doctors usually find latent TB by doing a tuberculin skin test. A doctor or nurse will inject TB antigens under your skin. If you have TB bacteria in your body, within 2 days you will get a red bump where the needle went into your skin. The test can't tell when you became infected with TB or if it can be spread to others. A blood test also can be done to look for TB.

To find TB in the lungs, doctors test a sample of mucus from the lungs to look for TB bacteria. Doctors sometimes do other tests or take a chest X-ray to help find TB in the lungs.

To find TB that's not in the lungs, doctors may take a tissue sample (biopsy) or do imaging tests.

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Treatment Overview

TB is treated with antibiotics to kill the TB bacteria. These medicines are given to everyone who has TB. This includes infants, children, and people who have a weakened immune system. These medicines can also be given during pregnancy.

TB can only be cured if you take all the doses of your medicine. If you miss doses, or if you stop taking your medicine too soon, your treatment may not work. Or it may have to go on longer.

A health professional may watch you take your medicine. This is called directly observed therapy (DOT). DOT is done to help make sure that you don't miss a dose and that all the bacteria are killed.

Surgery is rarely used to treat TB. But it may be used in severe or drug-resistant TB.

If you have latent TB, you may be treated with one or more antibiotics for many months.

The first phase of treatment for active TB lasts 2 months. During this phase, you take several different medicines. The second phase of treatment can last 4 to 7 months or longer. During this phase, the number of medicines you take may be reduced.

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Home treatment for TB focuses on taking the medicines correctly, taking good care of yourself, and protecting others from infection.

  • Take your medicines as prescribed.

    Taking your medicines correctly reduces your risk of getting multidrug-resistant TB.

  • Work with your doctor.
    • Go to all of your medical appointments.
    • Report any side effects of the medicines, especially vision problems.
    • If you plan to move during the time that you are being treated, let your doctor know. Your doctor can help arrange for you to keep getting treatment.
  • Help your body fight the infection.

    During treatment, eat healthy foods and get enough sleep and some exercise to help your body fight the infection.

    Ask your doctor when it's safe for you to exercise. When you can go outside, walking is a good way to get exercise. Start slowly if you haven't been active. Try to walk for a few minutes. Slowly increase your time as you feel stronger. Try to walk as often as you can.

  • Try to avoid too much weight loss.

    If you are losing too much weight, eat balanced meals with enough protein and calories to help you keep weight on. If you need help, talk with a registered dietitian.

    • If you don't feel like eating, try smaller meals several times a day instead of a few large ones.
    • Drink high-calorie protein shakes between meals. Or try nutritious drinks, such as Ensure.
    • If you feel sick to your stomach, try drinking peppermint or ginger tea.
  • Protect others from TB.

    Until you've been on antibiotics for about 2 weeks, you can easily spread the disease to others.

    • Don't go to work or school while you can spread the TB infection.
    • Sleep in a bedroom by yourself until you can no longer infect other people.
    • Open windows, if the weather allows it. This can help get rid of TB bacteria from the air in the room.
    • Cover your mouth when you sneeze or cough. After you cough, dispose of the soiled tissue in a covered container.
    • Wear a face mask when you are around other people.
    • Talk with your doctor about other things you can do to prevent the spread of TB.
  • Get support for emotional issues.

    Your doctor or health department can help you find a counselor or social worker to help you cope with your feelings. If you can't afford counseling or treatment, there may be places that offer free or less costly help.

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  1. Pasipanodya J, et al. (2015). Tuberculosis and other mycobacterial diseases. In ET Bope et al., eds., Conn's Current Therapy 2015, pp. 411–417. Philadelphia: Saunders.


Current as of: June 12, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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