Seasonal allergic rhinitis is not a major disease, but it is a chronic disease with a high incidence, and there are at least tens of millions of patients suffering from this disease in China. Once the disease strikes, it will recur year after year, seriously affecting the quality of life and daily routine, and the necessary daily therapeutic drugs add to the medical burden on families and the government. Most importantly, nearly half of summer and fall hay fever patients are likely to develop seasonal allergic asthma within 9 years of their first attack, a process that takes 5-10 years. The results of a clinical study completed by the Department of Allergic Reactions of Peking Union Medical College Hospital in recent years on a large sample of summer and fall hay fever patients showed that 53% of 1,096 patients with summer and fall pollen-induced allergic rhinitis had combined seasonal asthma. Not all patients with hay fever will develop asthma. 37% of all summer and fall hay fever patients will develop seasonal asthma within 5 years and 47% within 9 years of the rhinitis episode. Very few patients may develop summer and fall pollen-induced asthma 20-30 years after a rhinitis episode.