Objectives : The objective of this study is to study the effects of hot aqueous extract and ethanol extract from Paeoniae Radix Rubra on nitric oxide(NO) and prostaglandin $E_2(PGE_2)$ production in macrophage. Methods : Paeoniae Radix Rubra were extracted in 2 ways. one was extracted with hot aqueous for 4 hr in $100^{circ}C$ and the other one was extracted with 70% ethanol for 4 hr in $70^{circ}C$. RAW264.7 cells, a mouse macrophage lines, were incubated with different concentrations of the extract for 30 min and then stimulated with LPS at indicated times. Cell toxicity was determined by MTT assay. The concentrations of NO and $PGE_2$ were measured by griess assay and enzyme immunoassay(EIA). Results : The hot aqueous and ethanol extracts of Paeoniae Radix Rubra significantly inhibited the NO productions in LPS-stimulated RAW264.7 cells. The hot water extract of Paeoniae Radix Rubra significantly inhibited the $PGE_2$ productions in LPS-stimulated RAW264.7 cells. Conclusions : Our results demonstrated that Paeoniae Radix Rubra extract is able to significantly inhibit the production of NO, $PGE_2$ expression. Hot aqueous extract of Paeoniae Radix Rubra has more effective anti-inflammation than ethanol extract.