Oseltamivir phosphate granules are mainly used for the anti-infective treatment of influenza virus and can be used for the treatment of influenza A and B in adults and children aged 1 year and older, as well as for the prevention of influenza A and B in adults and adolescents aged 13 years and older. The dosage of oseltamivir phosphate granules for children is mainly calculated according to kilogram weight for children over one year old. For those weighing less than fifteen kilograms, thirty milligrams is administered twice a day. For weight between fifteen and twenty-three kilograms, forty-five milligrams twice a day. For body weight between twenty-three and forty kilograms, sixty milligrams once, twice a day. For body weight above forty kilograms, seventy-five milligrams twice a day may be given once. The most common adverse reaction to oral oseltamivir phosphate granules in children is vomiting. Other more common adverse reactions are abdominal pain, epistaxis, earache, and conjunctivitis. These adverse reactions usually occur only once and may be relieved by continued dosing. In most cases, they do not lead to discontinuation of therapy. The safety and efficacy of oseltamivir phosphate granules in the treatment of influenza in children under 1 year of age has not been established, and therefore should be used with caution in children under 1 year of age.