Zheng Duanyou was a pediatric physician of the Southern Song dynasty. His life, including his birth and death years, cannot be reliably determined, and the available public information is limited. His surviving work, Quanying fanglun (also known as Baoying quangfang), is an important pediatric text of the Song period, devoted to the diagnosis and treatment of childhood diseases. It discusses the causes, symptoms, and prescriptions for common pediatric conditions, reflecting the Song medical preference for attending to children's constitutional characteristics and for treatment based on pattern differentiation. The book was occasionally quoted in later pediatric works and retains some value for understanding the level of Southern Song pediatric practice and the compilation of medical formularies. Because the historical records are fragmentary, his native place, medical career, and scholarly lineage are undocumented, and his medical outlook can only be glimpsed through this extant work.
