Objective: To study effects of extracts from Portulacae Herba on spatial learning performance in senile mice induced by D-gal

and to explore the related mechanism. Method: The experimental mice were randomly divided into 5 groups:control group

model group and the n-butanol extracts from Portulacae Herba (0.5

0.25 g ·kg-1 ) groups

the ethanol extracts from Portulacae Herba (1

0.5 g ·kg-1) groups.Except the control group was given sc normal saline in the cervical back part.The rest of the mice were given sc D-gal(1 g ·kg-1) once daily continually for 42 days

while the mice were given medicines accordingly.Learning and memory performances were tested with Morris water maze test

and the content of malondialdehyde (MDA) in brain tissue of the senile mice

and the activities of superoxide dismutase(SOD) and lutathione peroxidase(GSH-Px)were determined. Result: The n-butanol extracts from Portulacae Herba (0.5

0.25 g ·kg-1) groups and the ethanol extracts from Portulacae Herba (1 g ·kg-1) group could obviously shorten the escape latency in senile mice.The n-butanol extract (0.5 g ·kg-1)and the ethanol extracts from Portulacae Herba (1

0.5 g ·kg-1) groups showedincrease in the frequency of passing the plateform within 1 min for the mice.The ethanol extracts (1 g ·kg-1) groups could decreases content of MDA and improve activity of SOD and GSH-Px in brain tissue.The ethanol extracts (1 g ·kg-1) groups could decrease content of MDA. Conclusion: The different extract from Portulacae Herba can ameliorate the spatial learning and memory performances of senile mice.The mechanism may be related to decrease in MDA in brain tissue and increase in activities of SOD and GSH-Px.The n-butanol extract from Portulacae Herba appears to be better than the ethanol extract from Portulacae Herba.