The principles of chemotherapy for pulmonary tuberculosis include early, appropriate dosage, full course, combination, and regularity: 1. Early means that once tuberculosis is clearly diagnosed, anti-tuberculosis treatment should be started immediately. 2. Regularity means that anti-tuberculosis drugs should be taken regularly in the course of anti-tuberculosis treatment, following medical advice and never stopping or changing the dosage of drugs without authorization. 3. The right amount means that the anti-tuberculosis drugs must be given in sufficient quantity to kill the tuberculosis bacilli. 5. Some may take up to 12-18 months or even 24 months.