The duration of the rash that can occur after taking TB drugs varies from person to person and there are no data to support this. The appearance of a rash after using anti-tuberculosis drugs needs to be considered as an allergic reaction caused by the use of tuberculosis drugs. There are many types of drugs for tuberculosis, and some people will develop a red rash when drug allergy occurs after using anti-tuberculosis drugs, but there is no data to support the exact time. If it is relatively mild, you can stop using the anti-tuberculosis drugs for a while and take anti-allergy drugs such as loratadine under doctor’s supervision. If the rash does not worsen with the anti-allergy drugs, you can continue to take the anti-TB drugs, but under close observation. If the rash continues to worsen after the use of anti-allergy drugs, you can stop taking the TB drugs under the guidance of your doctor and wait until the allergy is under control before making any adjustments. Patients with severe allergic reactions should stop anti-tuberculosis treatment in time for anti-allergy and rehydration therapy. If there is a symptom of a red rash that occurs after taking tuberculosis drugs and continues unrelieved, timely medical treatment is needed.