ObjectiveTo investigate the possible mechanism of Fugan Huaxian Decoction （扶肝化纤汤， FHD） against hepatic fibrosis （HF） from the perspective of immunity. MethodsForty-eight SD rats were randomly divided into blank group， model group， colchicine group， FHD high-， medium- and low-dose group， with eight rats in each group. Except for the blank group， the disease-syndrome combined model of HF with healthy qi deficiency and toxin accumulation pattern was established during six weeks in the other five groups. After successful modeling， the high-， medium- and low-dose FHD groups were respectively given 37.5， 18.75 and 9.38 g/（kg·d） of FHD granules by gavage， while the colchicine group received 2 mg/ （kg·d） of colchicine tablets by gavage， and the blank group and the model group were given 10 ml/（kg·d） of purified water， all for 3 weeks. The general condition of the rats was recorded. After the treatment， the histopathological morphology of the liver was observed by HE staining， and the levels of interleukin 10 （IL-10） and interleukin 17 （IL-17） in serum were determined by enzyme-linked immunosorbent assay （ELISA）. The expression of helper T cells 17 （Th17） and regulatory T cells （Treg） in peripheral blood were detected by flow cytometry， and the Th17/Treg value was calculated. The mRNA expression of retinoic acid-related nuclear orphan receptor γ （RORγt） and fork-head/wing-like helix transcription factor （FoxP3） in liver tissue were detected by qRT-PCR. ResultsCompared to the general condition of rats in the blank group， those in the model group were listless， less active， stretched and pushed， arched and prone， having no resistance to gavage， significantly reduced food intake， loose stools， dirty anus， slow weight gain， dry and dull hair， purple and darkening skin of the limbs with ecchymoses， purple and black spots with varying degrees of the skin of the tail； hepatic fibrosis and hyperplasia of rats in model group were more obvious； serum IL-17， peripheral blood Th17 expression and Th17/Treg value， RORγt mRNA expression in the liver tissue significantly increased in the model group， while expression of IL-10， Treg and FoxP3 mRNA significantly decreased （P＜0.05 or P＜0.01）. Compared to those in the model group， the general condition of the rats and the liver fibrosis of HE stained liver tissue were improved in all the medication groups； the expression of IL-17 and Th17， Th17/Treg， and RORγt mRNA expression significantly decreased， while expression of IL-10， Treg， and FoxP3 mRNA increased in the high- and medium-dose FHD groups and the colchicine group； the expression of IL-17， Th17， and RORγt mRNA decreased， while the expression of IL-10 and FoxP3 mRNA increased in the low-dose FHD group （P＜0.05 or P＜0.01）. And more improvements were found in the FHD high-dose group than FHD medium- and low-dose groups and colchicine group （P＜0.05 or P＜0.01）. ConclusionFHD can may regulate immune balance and act against fibrosis by regulating the expression of specific transcription factors FoxP3 and RORγt， affecting the differentiation of Th17 and Treg cells and Th17/Treg balance， and regulating the secretion of IL-10 and IL-17.