Objective: To study the analgesic and anti-inflammatory actions of Yuanshengtong formula (YSTF)

as well as the acute toxicity of YSTF. Method: The median lethal dose (LD50) of YSTF to mice was calculated with Bliss method. Writhing method and hot plate method in mice and tenderness test in rats were used to evaluate the analgesic effect. Paw swelling caused by carrageenan in rats

increased permeability of abdominal cavity induced by acetic acid in mice

adjuvant arthritis model in rats was established by Freund's complete adjuvant. The anti-inflammatory effect of YSTF was evaluated. Result: The LD50 of YSTF was 30.10 g·kg-1 with the 95% confidence range of 25.85-34.66 g·kg-1. YSTF had prominent analgesic and anti-inflammatory effects both in mice at 0.184 and 0.369 g·kg-1 and more than 0.184 g·kg-1 in rats. Conclusion: YSTF has significant analgesic effect and exhibits low toxicity. It can be applied to slow down rheumatic arthritis and other disease with sharp pain.