Tuberculosis is a clinically infectious respiratory disease that is transmitted mainly by droplets and is mostly caused by Mycobacterium tuberculosis infection. For TB patients themselves, the disease is usually contagious for 1-3 months after the disease, which is the active phase of the TB lesion. During this period, the patient needs to cooperate with the doctor’s treatment, and after 3 months, the infection will gradually decrease or even disappear. It is not possible to determine how many days a person can be infected because it is affected by the duration of contact with the patient, the degree of contact, the individual’s physical condition, and other factors. If one has ordinary contact with the patient, such as greeting from a distance of more than 1 meter, and one has a high immunity, one may not be infected with TB. However, if you have more intimate contact with a TB patient, such as hugging, or if your immunity is poor, you are more likely to contract TB. Therefore, if you suspect that you have tuberculosis, you need to go to the hospital and have a detailed examination. In addition, if the diagnosis is confirmed, anti-tuberculosis treatment is required in a timely manner, and the length of treatment is determined by the patient’s condition. For example, some patients who are sensitive to drugs can improve their symptoms in a short time and even eliminate Mycobacterium tuberculosis in their bodies; some patients who are not sensitive to drugs may take a longer time to treat. In addition, it is recommended that patients with tuberculosis should reduce their visits to public places or crowded places in the early stages of the disease, i.e., within 3 months, to avoid cross-infection.