Objective To study best decocting time of Yinqiao San against influenza A virus. Methods The researchers prepared powder of Yinqiao San respectively into solutions with concentration 0. 25 g / ml（ low）

0. 50 g /ml（ medium） and 1. 00 g / ml（ high）. Timing after those solutions were heated to 100℃

the three solutions were respectively boiled for 3

6

12 min and reposited in 4℃ to standby. Fifty-five SD rats were randomly divided into normal control group

influenza virus group

3 min group（ high

medium and low concentration）

6 min group（ high

medium and low concentration）

12 min group（ high

medium and low concentration）. The 3

6

12 min groups were given solutions of Yinqiao San with the corresponding concentration to gavage. The normal control group and the influenza virus group were given equal normal saline

2ml each time

twice a day for five days. Took blood from abdominal aorta to prepare medicated serum. Rat-lung adapted strains of influenza A virus（ FM1） was used to stimulate macrophage strains（ Ana-1） of rats under intervention with medicated serum with Yinqiao San with different decocting time and absorbed supernatant after those were cultivated for 24 h. Expression of toll-like receptors type 3

4（ TLR3

TLR4） mRNA and protein and mRNA of factors（ My D88

TRAF-6

TRIF

TRAM） related with dependent and independent pathway of its downstream myeloid differentiation factor（ My D88） were determined. Results Compared with the normal control group

expression levels of TLR3

TLR4

My D88

TRAF-6

TRAM

TRIF mRNA in the influenza virus group significantly increased（ P

<

0. 05）. Under intervention with Yinqiao San with different decocting time and concentration

TLR3

TLR4

My D88

TRAF-6

TRAM and TRIF mRNA of cells in each treatment group significantly decreased（ P

<

0. 05）

especially apparent in the 3 min group of medium and high concentration.There was statistically significant difference from the 12 min group with the same concentration（ P

<

0. 05）. Compared with the influenza virus group

the 6 min group with medium concentration significantly inhibite the expression of TLR3 protein（ P

<

0. 05）. In the 3 min group and the 6 min group with each concentration the content of TLR4 protein was reduced（ P

<

0. 05）. Compared with the 12 min group with the same concentration

the 3 min group with high concentration and the 6 min group with medium and high concentration had significant inhibition to expression of TLR4 protein（ P

<

0. 05）. Conclusion Best decoction time of Yinqiao San against influenza A virus was probably3

6 min after boiling.