To investigate the therapeutic effects of Qingre Quyu Granule (ae...c integral cyen > c similar to Euroe cent uc(2)', QQG) on the patients with severe carotid stenosis, and to explore the mechanism of it. Ninety-six patients with severe carotid stenosis were enrolled in the study and were classified into a QQG group (n=48) and a control group (n=48) randomly using consecutively numbered envelopes. The patients in the QQG group were given QQG and Western medicine, those in the control group were given Western medicine merely, the course of treatment was 16 weeks. All patients went through endarterectomy after treatment. Plaques were subjected to the analysis of CD3, CD68, soluble intercellular adhesion molecule 1 (ICAM-1), matrix metalloprotease-9 (MMP-9), CD40L, tenascin-C, and collagen content lipid content by immunohistochemistry or polarized light analysis. By the end of experiment, the expressions of CD3, CD68, ICAM-1, MMP9, CD40L and tenascin-C on the plaques were statistically significant lower in the QQG group compared with the control group(P < 0.01). The lipid content of the plaque was also significantly lower in the QQG group compared with the control group (P < 0.01). The interstitial collagen in the tissue sections of the plaques was also significantly higher in the QQG group in comparison with the control group (P < 0.01). QQG could stabilize carotid artery plaques through inhibiting pro-inflammation factors and restraining the tenascin-C and MMP9 pathway.