Objective To observe Th17 cells, Treg cells and their related factors in peripheral blood of children with milk protein allergy and explore the influence of Yupingfeng granule on Th17 / Treg imbalance and its clinical effect. Methods 40 children with milk protein allergy were divided into two groups randomly: the conventional treatment group (n=20), Yupingfeng granule group (n=20). The conventional treatment group received conventional treatment for 2 months. On the basis of routine treatment, Yupingfeng granule group was additionally treated with Yuping feng granule. The serum Th17, Treg cell counts, interleukin (IL)-17 and transforming growth factor-β1 (TGF-β1) levels were detected, and the eczema area and severity index (EASI) score of rash in children was recorded. Results The levels of Th17 cells and IL-17 in allergy children were obviously increased compared with those of the normal children, while the Treg cells, and the TGF-β1 level were lower than those of the normal children (P<0.05). After treatment, the Th17 cells, the IL-17 levels and ESAI scores of the conventional treatment group and the Yupingfeng granule group were lowered, while the Treg cells and the TGF-β1 levels were increased (P<0.05). Compared with the conventional treatment group, these indexes increased and decreased more significantly in the Yupingfeng granule group (P<0.05). Conclusions Milk allergy children have obvious imbalance of Th17/Treg; the Yupingfeng granule can adjust this imbalance and alleviate the allergic symptoms of milk protein. Key words: Milk proteins/AE; Milk hypersensitivity/DT; YUPINGFENG POWDERS/TU; Th17 cells/IM; T-lymphocytes, regulatory/IM; Child