Keratan is a common anti-allergy medication that is an H1 receptor blocker. The usual clinical dose for adults is 10mg once a day. Children are generally 2-12 years old and can be given 5-10mg depending on the circumstances. for those under 2 years old, generally 1 month to 2 years old, 3-5ml is given. The safety of the children’s amount of Kerratan is basically okay, and it can even be used during pregnancy, especially in the middle and late stages of pregnancy, with a better safety profile. Keratan use has a period of time to be different according to different diseases, for example, allergic rhinitis is usually used for about 3-4 weeks. Instead of taking it once or twice and not using it after normal relief, this method of taking the medicine is not right, and it does not help much in suppressing the sensitivity factor and allergic factor in the body.