Abstract: OBJECTIVE To investigate the anti-inflammatory effect of Aconiti Lateralis Radix Praeparata combined with Paeoniae Radix Alba on the arthritic rat. METHODS The rat model was established by injecting the complete Frund’s adjuvant into the subcutis of their left rear paws. The rats were randomly divided into control group, model group, tripterygium glycosides group, Aconiti Lateralis Radix Praeparata group, Paeoniae Radix Alba group and combinational group(treated with Aconiti Lateralis Radix Praeparata and Paeoniae Radix Alba). Meanwhile, the volume of paw swelling was measured, and the serum levels of PGE2, IL-1β and TNF-α were detected by ELISA. RESULTS Compared with model group, the tripterygium glycosides group, Aconiti Lateralis Radix Praeparata group, Paeoniae Radix Alba group and combinational group could decrease the swelling degree of the rat paws and decrease the serum concentration of PGE2, IL-1β,TNF-α. And the combinational group, tripterygium glycosides group, Paeoniae Radix Alba group had the strongest effect (P<0.01), Aconiti Lateralis Radix Praeparata group and Paeoniae Radix Alba group were weaker than the combination group, the weakest inhibitory action of aconite group, with significant difference with compound group(P<0.01). CONCLUSION Both of Aconiti Lateralis Radix Praeparata and Paeoniae Radix Alba treatment group have obviously anti-inflammation activity. the combination treatment can significantly enhance the anti-inflammation activity of any single one. It may indicate that synergy effects are generated during the combinational treatment of the two herb.