Ketotifen is a drug whose main indication is the prevention of exogenous, endogenous and mixed asthma attacks, and its efficiency can reach more than 65%. Many patients have significantly fewer attacks and less symptoms after using the drug, and the treatment effect for children’s asthma may be better than that for adults. The effect of exogenous asthma is produced faster than endogenous asthma, and it can be taken orally. It is mainly used for a variety of allergic diseases. For example, bronchial asthma, wheezing bronchitis or allergic asthma, allergic rhinitis, allergic hay fever and conjunctivitis, acute or chronic urticaria, contact dermatitis, photosensitivity dermatitis, food allergic reactions, drug allergic reactions and insect allergic reactions. It works mainly for symptoms related to allergic reactions.