Both nitric oxide (NO) and interleukin-6 (IL-6) have been thought to have a role in the pathogenesis of inflammatory periodontal disease as it does in other inflammatory diseases, and the inhibitors of NO and IL-6 production have been considered as potential anti-inflammatory agents. In this study, we evaluated methanol extract of Sophorae Flos for inhibition of NO and IL-6 production in Prevotella intermedia LPS-induced mouse macrophages RAW264.7 cells. Dried Sopharae Flos was sliced, and extracted with 100% methanol. LPS from p. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. NO production was assayed by measuring the accumulation of nitrite in culture supematants and IL-6 was measured using mouse IL-6 ELISA kit. Western blot analysis of iNOS and analysis of reverse transcription (RT)-PCR products were carried out. The methanol extract of Sophorae Flos concentration-dependently reduced the production of NO and the expression of iNOS protein and mRNA in RAw264.7 cells treated with P. intermedia LPS. Sophorae Flos also suppressed IL-6 production and the expression of IL-6 mRNA in RAw264.7 cells stimulated by P. intermedia LPS. The inhibition of NO and IL-6 production by Sophorae Flos may be useful in the therapy of inflammatory diseases such as periodontitis. This hypothesis, however, remains to be tested.