Patients often ask that for common bacterial infections, they can be largely cured with medication for about half a month. However, the reason why it takes more than half a year to treat tuberculosis infection is related to the family of tuberculosis bacteria. In the 1950s, some foreign scientists observed the existence of stubborn bacteria in the tuberculosis flora, and thus divided the bacteria in the tuberculosis lesion into four groups, namely fast-growing bacteria, intermittent-growing bacteria, slow-growing bacteria and dormant bacteria, which are generally called A, B, C and D flora in clinical practice. B and C flora can be maintained for several months or years, or even wake up again after a period of time. Therefore, B and C flora are often the main flora causing relapse of tuberculosis. The purpose of a long course of treatment is to prevent the recurrence of tuberculosis by killing the persistent bacteria during the process of their gradual reawakening by the anti-tuberculosis drugs being used at the time. Even if the patient’s symptoms are completely relieved in the early stage of medication, he or she should continue to use anti-tuberculosis drugs to prevent a relapse at a later stage, and should not stop medication at will because he or she feels well. If there is a relapse of tuberculosis and the medication is used again, the patient’s course of treatment may be longer, and the medication may be more complicated and cause more trouble for the patient.