Objective To observe the effect of pigplacenta ins tead of Ziheche （P lacenta Hominis） for the treatment of senile dementia. Methods Seventy Kunming mice were divided into blank group

model group

pos itive control group

Zih eche low and high dosage groups

and pigplacenta low and high dosage grou ps

wi th 10 in each. The senile dementia models were established with the D-Galactose subcutaneous injection. The blank group was not administered any medicines. The model group was prescribed normal saline instead of the tested medicine; the pos itive control group was given Naofukang by gavage; the Zih eche low and high dosage groups were given 2g/kg and 4g/kg Ziheche respectivel y by gavage; while the pigplacenta low and high dosage groups were treated wi th p igplacenta 4g/kg and 8g/kg respectively by gavage. After treatment for 6 week s

the behavior experimental dark-avoiding test and step-down test were applied to test the effect of the medicines on the learning memory of mice

and acetylchol inesterase and monoamine levels in brain tissues. Results There was no s ignificant difference between the effect of pigplacenta and Ziheche in resi stin g senile dementia. In the latency of dark-avoiding test

the effect of high d osa ge of pigplacenta was significantly better than that of Ziheche （P<0.01）. T he e ffect of pigplacenta and Ziheche on monoamine was similar with each other. Con clusion It’s possible to use pigplacenta instead of Ziheche for the treatment of senile dementia.