Objective: To explore the therapeutic effect and the possible working mechanism in using Chinese herbal medicine (CHM) for supplementing Kidney and Qi

and activating blood circulation in treating intrauterine growth retardation of fetus (IUGR). Methods: Fifty-five cases of IUGR were divided into two groups

30 cases in the CHM group treated with CHM and the 25 in the control group treated with amino acids. The effect of CHM treatment was observed and compared with that of the control group

normal pregnancy group and non-treated IUGR group. Results: Body weight of the newborns in the CHM was markedly higher than that in the control group. Not only the maternal fundal height (FH) and the abdominal circumference (AC)

but also the fetal growth parameters

including biparietal diameter

head circumference (HC)

and femur length (FL) in the CHM group increased much faster than those in the control group. After CHM treatment

the maternal serum levels of estriol (E3) and human placental lactogen (hPL) approached to those in the normal pregnancy group

but the control group

in comparison with the normal pregnancy group

was significantly different. The umbilical venous plasma concentration of essential amino acids in both treated groups improved

but the improvement in the CHM group was more significant than that in the control group. No apparent adverse effect of CHM was observed in either mother or fetus. Conclusion: CHM for supplementing Kidney and Qi and activating blood circulation was more effective in improving placental function and enhancing amino acid transportation than amino acid.