Objective To study the immunomodulatory effect of Qiguiyin Formula[formula of Huangqi（Radix Astragali）

Danggui（Angelica Sinensis）and Jinyinhua（Flos Lonicerae）]on rats with multidrug-resistant pseudomonas aeruginosa infection.Methods The SD rats were randomized into the blank group

model group

western medicine control group

Qiguiyin Formula group and integrative medicine group

with 8in each.The multi-drug resistant pseudomonas aeruginosa bacteria and 2.0%tragacanth were mixed at one to one ratio and 8ml/kg of the mixture was intraperitoneally injected to the rats in each group except the blank group.After injection

the blank group and model group were gavaged with 2ml distilled water

the western medicine control group was intramuscularly injected with 0.45g/kg ceftazidime

the Qiguiyin Formula group was gavaged with 2ml（1.0g/ml）Qiguiyin Formula extract and the integrative medicine group was gavaged with Qiguiyin Formula extract and intramuscularly injected with ceftazidime.The spleen tissue specimens were taken 3 hours after intraperitoneal infection.The proliferation levels of T and B lymphocytes were detected by MTT method.Results Comparing with the blank group

the proliferation levels of T and B lymphocytes were significantly increased in the model group（P<0.05 or P<0.01）.Comparing with the blank group

the proliferation levels of T and B lymphocytes were significantly decreased in the western medicine control group（P<0.05or P<0.01）.Comparing with the blank group

the proliferation levels of T and B lymphocytes were not significantly changed in the Qiguiyin Formula group and integrative medicine group（P>0.05）.Comparing with the model group

the proliferation levels of T and B lymphocytes were significantly decreased in the western medicine control group

Qiguiyin Formula group and integrative medicine group（P<0.05or P<0.01）.Conclusion Qiguiyin Formula can moderately down-regulate the lymphocyte proliferation in rats with multidrug-resistant pseudomonas aeruginosa infection.Comparing with the excessive inhibition of immune response by ceftazidime

Qiguiyin Formula can balance the immune disorders caused by infection.