Tuberculosis four-in-one drug usually refers to the first-line antituberculosis drugs rifampicin, isoniazid, pyrazinamide, ethambutol four types of drugs used in combination. 1. Rifampicin: It has a certain bactericidal effect on both intracellular and extracellular tuberculosis bacteria, and the mechanism of bactericidal is to inhibit the synthesis of bacterial RNA. The main adverse reactions include gastrointestinal discomfort and liver function impairment. 2. Isoniazid: It can be taken orally, has little side effects and is inexpensive, with good therapeutic effect, and is commonly used in the treatment of tuberculosis. Adverse reactions are rare, mainly peripheral neuritis, liver damage. 3. Pyrazinamide: it can be used for short-term chemotherapy of tuberculosis, the main adverse reactions include hyperuricemia and hepatitis. 4. Ethambutol: it can effectively sterilize tuberculosis by inhibiting RNA synthesis of tuberculosis bacteria. Common adverse reactions include allergic reaction, drug rash and so on. The above drugs should be used under the guidance of a doctor. TB 4-in-1 drugs can also be used individually, but the therapeutic effect is usually not as good as the combined use. TB patients should go to the hospital promptly and actively cooperate with the treatment under the doctor’s guidance and advice if any discomfort or serious adverse reaction occurs during the use of the drug.