Objective: To investigate the influence of the extracts of Folium Artemisiae argyi (FAA) with different extraction methods (by water

by ethanol

firstly by water then by alcohol) on the primary dysmenorrheal model in mice and to clarify the potential mechanism. Method: The ICR mice were randomly divided into nine groups

including normal control group

model group

masculine control group and the extract of FAA extracted with different preparation method groups (low and high dosage

0.55

1.65 g·kg-1 accordingly). Except the control group

all the other groups were injected subcutaneously estradiol benzoate (10 mg·kg-1) with seven consecutive days

and then these mice were injected intraperitoneally oxytocin (10 mL·kg-1) at the eighth day so that the primary dysmenorrheal model was established. All the groups were orally administered once pre day with four consecutive days after the model has been made for 5 days. The mouse model of primary dysmenorrheal was used to study the effect of FAA extracted with different preparation methods (low dose and high dose) on writhing response and the levels of nitric oxide(NO) and calcium ion(Ca2+) in mice uterine tissue. Result: The ethanol extract in high dosage of FAA and the water alcohol mixture extract in both dosages of FAA could increase pain threshold markedly

and the inhibitory rate was 36.9%

52.5% and 42.2% (P<0.01)

respectively. Furthermore

the solution of FAA extracted firstly by water then by alcohol showed the stronger effect than the water extract at the same dosage by reducing the writhing times (P<0.05). In addition

the ethanol extract in high dosage of FAA and the water alcohol mixture extract in both dosages of FAA showed significant effect on primary dysmenorrhea by increasing NO concentration and reducing Ca2+ concentration in uterine tissue (P<0.01). Conclusion: The different extracts of FAA showed different antidysmenorrheic trend on primary dysmenorrhea model mice

which were related with the containing constituents. In three extracts of FAA

the water alcohol mixture extract showed stronger analgesic activity than that of the ethanol extract

and the water extract had the weakest activity.