It is generally accepted that there are four different states of bacilli in TB lesions: group A is continuously growing and reproducing, group B is intermittently reproducing, group C is semi-dormant in an acidic environment, and group D is completely dormant. The first-line antituberculosis drugs are not effective against all metabolic states, for example, streptomycin is completely ineffective against group C bacteria, and only pyrazinamide has the strongest effect on this group. group B and C tuberculosis bacteria can remain in the body for a long time, and chemotherapy drugs should be used for a sufficient duration to kill them. Therefore, if the chemotherapy drugs used are inappropriate or insufficient, group B and C tuberculosis bacteria cannot be destroyed and relapse can easily occur.