How long to take anti-tuberculosis drugs have allergic reactions need to be based on the patient’s own situation, usually the anti-tuberculosis drugs may have allergic reactions after taking 7 to 14 days of time. Some patients with tuberculosis may have some adverse reactions after taking anti-tuberculosis drugs, and the time of side effects may vary among different groups of people. Usually, after 7 to 14 days of taking the drugs, there may be rashes, itching, fever, and at the same time, it may stimulate the bronchial tubes to secrete more substances, which may cause allergic reactions such as dyspnea in some patients. Tuberculosis patients taking anti-tuberculosis drugs for treatment, if there is a history of allergy, should inform the doctor in advance, under the guidance of the doctor according to the patient’s specific symptoms to adjust the treatment program, and do a good job of isolation measures to avoid cross-infection.