Abstract：Objective：To discuss the improvement mechanism of Shuangguo Houle tang on rats with acute pharyngitis. Methods：A total of 60 rats were randomly divided into the control group，the model group，the dexamethasone group，the Shuangguo Houle tang groups with high dose，medium dose，and low dose，10 rats in each group. Except for the control group，rat models with acute pharyngitis were established in the other groups. After successful modeling，the model group and the control group were given gastric perfusion with same volume of normal saline； the Shuangguo Houle tang groups with high dose， medium dose， and low dose as well as the dexamethasone group were respectively treated with gastric perfusion with the corresponding dose of medicines for seven days. The pathological condition was observed in each group. The contents of interleukin- 1β(IL- 1β)，interleukin- 6(IL- 6)，tumor necrosis factor- α(TNF- α)，and prostaglandinE2(PGE2) were detected in each group. The expression levels of mRNA of ERK1/2 and COX- 2 in the pharynx were detected in each group. The expression levels of protein of ERK1/2 and p- ERK1/2 in the pharynx were detected in each group. Results： In comparison with those of the control group， the pathological conditions of the model group were as following： disorderly arrangement of the pharynx cells， severe keratosis of mucosal epithelium， infiltration of massive inflammatory cells， significant proliferation of epithelial layer， vasodilatation and hemorrhage in mucosa， and the increased number of glands. When compared with those in the control group，in the model group，the contents of TNF-α，IL-1β，IL-6，and PGE2 in serum，the expression levels of mRNA of ERK1/2 and COX-2 in the pharynx，as well as the expression levels of protein of COX- 2 and p- ERK1/2 in the pharynx were increased(P＜0.05). When compared with those in the model group， in the dexamethasone group as well as the Shuangguo Houle tang groups with high dose， medium dose， and low dose， the contents of TNF- α， IL- 1β， IL- 6， and PGE2 in serum， the expression levels of mRNA of ERK1/2 and COX- 2 in the pharynx ，as well as the expression levels of protein of COX-2 and p-ERK1/2 in the pharynx were decreased(P＜0.05). When compared with those in the dexamethasone group，the contents of TNF- α，IL- 1β，IL- 6，and PGE2 in serum，and the expression levels of mRNA of ERK1/2 and COX-2 in the pharynx in the Shuangguo Houle tang groups with medium dose and low dose were higher(P＜0.05)；the expression levels of protein of COX- 2 and p- ERK1/2 in the pharynx in the Shuangguo Houle tang group with low dose were higher(P＜0.05). When compared with those in the dexamethasone group， in the Shuangguo Houle tang group with high dose，the contents of IL-1β，IL-6，and PGE2 in serum，and the expression level of mRNA of ERK1/2 in the pharynx were higher(P＜0.05)， and the expression level of mRNA of COX- 2 was lower(P＜0.05). When compared with those in the Shuangguo Houle tang group with low dose，the contents of TNF-α，IL-1β，IL-6，and PGE2 in serum， and the expression levels of mRNA of ERK1/2 and COX- 2 in the pharynx in the Shuangguo Houle tang groups with high dose and medium dose were lower(P＜0.05)；the expression levels of protein of p-ERK1/2 and COX-2 in the pharynx in the Shuangguo Houle tang group with high dose were lower(P＜0.05). Conclusion：Shuangguo Houle tang has a significant improvement effect on rats with acute pharyngitis induced by ammonia water， which may be related to regulation of ERK1/2-COX-2-PGE2 signaling pathway