Objective To study the possible mechanism of Yanghe Huanyan Decoction（ 阳和化岩汤） in the treatment of breast cancer. Methods The tumor bearing model of Balb/c nude mice was established by inoculation of SK-BR-3 cell lines. The nude mice model of tumor was established and a total of 20 mice were randomly divided into model group

Chinese medicine（ CM） group

trastuzumab group and trastuzumab + CM group

with 5 mice in each group. The model group was given 0. 4 ml of normal saline every day; Yanghe Huayan Decoction 18 g/（ kg·d）was used for gavage in CM group. Trastuzumab group was given trastuzumab 1 mg/kg

2 times a week

intraperitoneal injection; Yanghe Huanyan Decoction and trastuzumab were given to the trastuzumab + CM groups

and the usage was the same as that in the CM and trastuzumab groups. The inhibition rate of lymph node metastasis was observed after 4 weeks administration. The expression of key target proteins PI3 K

p-Akt and vascular endothelial growth factor C（ VEGFC） in the PI3 K/Akt interaction pathway were detected by RT-PCR

and in tumor tissues was detected

and the number of lymphatic vessels and VEGFC score were counted. Results There were solid tumors in the mammary gland in each group

which were oval or lobulated

axillary lymph node metastasis was observed in nude mice with orthotopic breast cancer transplantation. Compared with the model group

the inhibition rate of lymph nodes increased in three treated group

VEGFC score and mRNA expression of PI3 K

p-Akt and VEGFC were decreased

and the number of microlymphatic vessels was decreased（ P < 0. 05 or P < 0. 01）. Compared with the CM group and the trastuzumab group

the lymph node inhibition rate was significantly increased in the trastuzumab + CM group

and VEGFC score

PI3 K

p-Akt and VEGFC mRNA expression were all decreased

and the number of microlymphatic vessels was reduced（ P < 0. 05 or P < 0. 01）. There was a positive correlation between VEGFC score and the number of microlymphatic vessels（ r = 0. 894

P < 0. 05）. Conclusion Yanghe Huanyan Decoction can effectively inhibit the formation of microlymphangiogenesis and the regulation pathway of angiogenesis and VEGFC expression in the tumor bearing model of nude mice with high HER-2 expression

and the mechanism may be related to the effective inhibition of the activation of PI3 K/Akt interactive regulation pathway.