Huangdi Neijing（Inner Canon of Huangdi）points out that yin-yang of the body is synchronized with yin-yang of four-season.Llife activities and pathological conditions have the time period and rhythm and four-season is inextricably linked to the occurrence

development and rehabilitation of disease.The scientific connotation of Four-Season Theory in Chinese medicine and the impact of four-season on disease especially the impact of seasonal variations on thalassemia were discussed in this article.Severe hemolysis is very common in the hot season in thalassemia patients.The hemoglobin level is negatively correlated with air temperature.Most thalassemia patients manifest liver-kidney yin deficiency syndrome and essenceblood deficiency syndrome.Thalassemia patients manifest severe symptoms of yin deficiency syndrome in the hot season.Therefore

we added Maidong（Radix Ophiopogonis

麦冬）in Yisui Shengxue Granules and achieved good efficacy.Environmental factors and seasonal changes should be considered in treatment for thalassemia.