Objective: To compare the effect of single and combined decoction of Angelicae Dahuricae Radix and Myrrha on the content of imperatorin and their analgesic effect.Method: The decoction of Angelicae Dahuricae Radix

Myrrha and their combined decotion were obtained by conventional decoction process.The content of imperatorin in different extract was determined by LC-MS.Mice were divided into blank group

positive drug group(paracetamol and dihydrocodeine tartrate tablets group

0.24 g·kg-1·d-1) and low

medium

high dose group of three kinds of decoction

the dose of single decoction of Angelicae Dahuricae Radix was set as 3

6

12 g·kg-1·d-1

the dose of single decoction of Myrrha was 1.5

3

6 g·kg-1·d-1

the dose of mixed decoction was 4.5

9

18 g·kg-1·d-1.Analgesic effect was tested by hot plate test and writhing test in mice after oral administration for 7 d.Result: The linear range of imperatorin was 0.02-0.20 mg·L-1(R2=0.991 1)

the transfer rate of imperatorin was 0.62% in single decoction of Angelicae Dahuricae Radix

but it reached 2.00% in mixed decoction.Except for some time points

there were significant differences between each dose group of single decoction

mixed decoction and the blank group by hot plate method(P<0.05

P<0.01).In the writhing test

there were significant differences between the low

medium dose of Angelicae Dahuricae Radix single decoction

high dose of Myrrha single decoction

each dose group of mixed decoction and the blank group(P<0.05

P<0.01).Conclusion: Mixed decoction of Angelicae Dahuricae Radix and Myrrha can promote the dissolution of imperatorin in Angelicae Dahuricae Radix.Each dose group of single and combined decoction can prolong the licking time of hot plate in mice

and all dose groups of combined decoction can prolong the latent period of torsional body.The high dose group of combined decoction has the highest inhibition rate of pain in mice.