The main active ingredient is loratadine, which is an anti-allergic drug, mainly through the inhibition of histamine, thus playing an anti-allergic effect. Histamine is a substance closely related to allergic reactions, loratadine is the inhibition of histamine related functions, is a highly effective and long-lasting tricyclic antihistamine, is a selective peripheral H1 receptor antagonist, can relieve the symptoms caused by allergic reactions. Keratan or loratadine tablets are mainly used for allergic diseases, such as relief of symptoms related to allergic rhinitis, such as sneezing, runny nose, nasal congestion, nasal itching, and itching and burning sensation in the eyes, and also for relief of eye symptoms. In addition, it can also be used to relieve allergic skin reactions, such as chronic urticaria, pruritus and other allergic skin diseases. In short, Keratan is not a hormonal drug, but an anti-allergic drug.