Abstract: This study was aimed to assess the effect of forsythiaside A on inflammatory cytokine interleukin-6（IL-6） level in lipopolysaccharide-treated spleen lymphocyte of chickens. Chicks were reared from the age of 1 to 50 days at normal management condition; at the age of 50 days, chickens were sacrificed and the heart blood samples were collected; the skin of the sacrificed chickens was disinfected and the spleen samples were collected; the spleen lymphocytes were subsequently isolated by lymphocyte separating medium; four treatment groups were set in this study, including the control group, LPS treatment group（5μg/m L）, low dosage forsythiaside A prevention group（5 μg/m L LPS＋200 μg/m L forsythiaside A）, and high dosage forsythiaside A prevention group（5 μg/m L LPS ＋400 μg/m L forsythiaside A）; the protein and m RNA expression level of IL-6 in spleen lymphocytes of different treatment groups were determined by ELISA and q RT-PCR assay respectively during a 48-hour time period at 0, 6, 12, 24 and 48 h. The ELISA assay results revealed that the level of IL-6 protein was found increased in the LPS group compared to the control group; both the low dosage and high dosage forsythiaside A prevention groups showed lower IL-6protein level compared to the LPS group, indicating that the change of the IL-6 protein level in chicken spleen was positively correlated with the dosage of forsythiaside A and forsythiaside A alleviated the inflammation in chicken spleen lymphocytes induced by LPS via inhibiting the increase of IL-6 protein level. The q RT-PCR results showed that LPS group had higher IL-6m RNA expression level compared to the control group; the level of IL-6 m RNA expression was lower in both the low dosage and high dosage forsythiaside A prevention groups compared to the LPS group, and the change of the IL-6m RNA expression level was negatively correlated with the dosage of forsythiaside A, which further demonstrated that forsythiaside A relieved the inflammation in chicken spleen lymphocytes induced by LPS through suppressing the increase of IL-6 m RNA expression in transcriptional level.The combined data suggest that forsythiaside A exerts anti-inflammation in lipopolysaccharide-treated spleen lymphocyte of chickens by inhibit the expression of IL-6 at transcriptional and translational level.