Abstract:The analgesia action was investigated in the pain model caused by formalin,and the content of NO,PGE2 and SOD of serum and spinal cord of mice with pain model caused by glacialaceticacid were also detected to study analgesia mechanism of Paeonia and Glycyrrhiza Decoction(PGD).The results indicate:(1)In Formalin pain experiment,PGD could restrain peripheral nerve twig action,and inhibit subesequent inflammatory reaction to ease pain in Ⅰ and Ⅱ phase reaction;(2)PGD could decrease the content of NO and PGE2 of serum and spinal cord of the mice and distinctly enhance the activity of SOD.