Control programs involve two major components. First, and of highest priority, is to detect persons with active tuberculosis and treat them with effective antituberculosis drugs, which prevents death from tuberculosis and stops the transmission of infection to other persons. Treatment of active tuberculosis involves taking multiple antituberculosis drugs daily or several times weekly for at least six months. Failure to take the medications for the full treatment period may mean that the disease is not cured and may recur. If sufficient medications are not prescribed early and taken regularly, the tuberculosis organism can become resistant to the drugs, and the drug resistant tuberculosis then may be transmitted to other persons. Drug resistant disease is difficult and expensive to treat, and in some cases, cannot be treated with available medications.