Dexamethasone is a long-acting glucocorticoid with anti-inflammatory and immunosuppressive effects. It is mainly used for allergic or autoimmune diseases, such as severe bronchial asthma, severe dermatitis, ulcerative colitis, acute leukemia, and connective tissue diseases. It is best to take dexamethasone with food to avoid gastrointestinal discomfort, and if the drug is to be taken only once a day, it is recommended that it be taken preferably every morning. After taking dexamethasone for a long time, if you stop taking the drug or gradually reduce the dosage according to your condition, you should follow the doctor’s prescription and advice, and avoid stopping the drug or reducing the dosage suddenly by yourself. This may cause the disease to recur, so be sure not to stop the drug without permission. Dexamethasone may cause a low immune system and make you susceptible to infections, so wash your hands frequently and stay away from people with colds during the medication. Vaccinations should not be given within 6 months after long-term use or discontinuation of the drug, as this will also increase the risk of infection.