Objective:To investigate the anti-inflammatory and immunoregulatory effects of Yupingfeng(玉屏风,YPF) Powder and its components in rats.Methods:A rat chronic bronchitis(CB) model was developed using lipopolysaccharide(LPS) combined with bacillus Calmette Guerin(BCG).YPF,simple recipe Astragalus membranaceus(Fisch.) Bge(AM) and Astragalus membranaceus(Fisch.) Bge plus rhizome of Atractylodes macrocephala Koidz(AM+RA) decoction were administered(intragastric administration,once a day for 21 days) to rats,to prevent and treat CB.Immunoregulatory and anti-inflammatory effects of YPF,AM and AM+RA were tested by serum pharmacology in vitro on splenic lymphocytes of normal rats and alveolar macrophages of CB rats.Results:Inflammation in the pulmonary tissue and the bronchus of CB rats was significantly reduced in the YPF-treatment groups,AM and AM+RA groups demonstrating the efficacy of YPF.Serum samples collected at different times from rats after administration of YPF,AM and AM+RA demonstrated increased proliferation of splenic lymphocytes with area under the effect curve(AUE) of 552.6%,336.3%and 452.0%,respectively. Treatment of alveolar macrophages with serum samples in YPF,AM or AM+RA group inhibited interleukin-8 (IL-8) in the cell culture media,and the effect was much better in the YPF group compared with AM or AM+RA group,with a higher maximal effect(E_(max),P<0.05) and larger AUE(P<0.01 and P<0.05).Moreover,serum from rats treated with AM or AM+RA had similar efficacy,while the efficiency was lower than that treated with YPF. Conclusion:YPF demonstrated anti-inflammatory and immunoregulatory effects in a rat model of CB,and timedependent relationships were demonstrated in vitro. Objective: To investigate the anti-inflammatory and immunoregulatory effects of Yupingfeng (YPF) Powder and its components in rats. Methods: A rat chronic bronchitis (CB) model was developed using lipopolysaccharide (LPS) combined with bacillus Calmette Guerin ), Simple recipe Astragalus membranaceus (Fisch.) Bge (AM) and Astragalus membranaceus (Fisch.) Bge plus rhizome of Atractylodes macrocephala Koidz (AM + RA) decoction were administered (intragastric administration, once a day for 21 days) to rats, to prevent and treat CB. Immunoregulatory and anti-inflammatory effects of YPF, AM and AM + RA were tested by serum pharmacology in vitro on splenic lymphocytes of normal rats and alveolar macrophages of CB rats. Results: Inflammation in the pulmonary tissue and the bronchus of CB rats was significantly reduced in the YPF-treatment groups, AM and AM + RA groups demonstrating the efficacy of YPF.Serum samples collected at different times from rats after administration of YPF, AM and AM + RA demons Treatment of alveolar macrophages with serum samples in YPF, AM or AM + RA group-only interleukin-8 (IL- 8) in the cell culture media, and the effect was much better in the YPF group compared with AM or AM + RA group, with a higher maximal effect (E max, P <0.05) and larger AUE Moverover, serum from rats treated with AM or AM + RA had similar efficacy, while the efficiency was lower than that treated with YPF. Conclusion: YPF demonstrated anti-inflammatory and immunoregulatory effects in a rat model of CB, and timedependent relationships were demonstrated in vitro