Objective:To observe the effect and mechanism of Xiaozheng wan for mouse melasma model of progesterone composed of UV radiation induced. Method: Female ICR mice were randomly divided into normal group

model group

Baixiao dan group (3 g · kg-1)

Xiaozheng Wan low-dose group (1 g · kg-1)

middle dose group (2 g · kg-1)

high-dose group (4 g · kg-1)

except the normal group and the model group was given normal saline

the rest of the group at the suggest doses administered by gavage for 36 days. And at the beginning of the administration except the normal group

the other groups were using progesterone intramuscular injection (20 mg · kg-1)

while 320 nm ultraviolet irradiation of one hour

once a day for 36 days

to cause chloasma mouse model. After the end of the experiment

measuring liver and skin tyrosinase (TYR)

superoxide dismutase (SOD)

malondialdehyde (MDA) content

the other to take part irradiated skin pathological and immunohistochemical determination of skin black cells. Result: The treatment group significantly reduced liver and skin TYR content

compared with model group with a significant difference (P<0.01);skin can reduce the content of MDA

but no significant difference;effect on the skin and liver SOD is low. Conclusion: Xiaozheng wan chloasma composite model in mice can inhibit melanin production role.