Abstract：Objective：To observe the curative effect of gargle with Modified Gancao Xiexin Decoction for chemotherapy- related oral mucositis. Methods： A total of 101 cases of patients with breast cancer chemotherapy- related oral mucositis were divided into the control group and the observation group according to the random number table method， with 50 and 51 cases in each group respectively. Both groups were given taxane chemotherapy；the control group was given gargle with Kangfuxin Liquid，and the observation group was given gargle with Modified Gancao Xiexin Decoction. The clinical effects in the two groups were evaluated； the healing time of oral mucosa， pain scores， oral pH values， traditional Chinese medicine (TCM) syndrome scores， the quantity of oral microorganisms and the levels of inflammatory factors were compared between the two groups. Results： The total effective rate was 98.04% in the observation group， higher than that of 82.00% in the control group (P＜0.05). After treatment， Visual Analogue Scale (VAS) scores， oral pH values， and TCM syndrome scores in the two groups were decreased when compared with those before treatment (P＜0.05)；VAS score，oral pH value and TCM syndrome score in the observation group were lower than those in the control group (P＜0.05)， and the healing time of oral mucosa in the observation group was shorter than that in the control group (P＜ 0.05). After treatment， the quantity of oral Streptococcus， Veillonella， and Neisseria in the two groups was increased when compared with that before treatment (P＜0.05). The quantity of oral Streptococcus， Veillonella，and Neisseria in the observation group was higher than that in the control group (P＜0.05). After treatment，the levels of hypoxia inducible factor-1α (HIF-1α)，interleukin-6 (IL-6)，transforming growth factor- β1 (TGF- β1)， and tumor necrosis factor- α (TNF- α) in serum in the two groups were decreased when compared with those before treatment (P＜0.05)，and the levels of HIF- 1α，IL- 6，TGF- β1，and TNF- α in the observation group were lower than those in the control group (P＜0.05). After treatment， neutrophil and white blood cell counts in the two groups were increased when compared with those before treatment (P＜0.05)； the count of neutrophil and white blood cell count in the observation group were higher than those in the control group (P＜0.05). Conclusion： Gargle with Modified Gancao Xiexin Decoctionin for breast cancer chemotherapy- related oral mucositis can improve the quantity of oral microorganisms，inhibit body inflammation，increase neutrophil and white blood cell counts，improve oral environment，promote oral mucosal healing，relieve patients' pain，and enhance clinical effects.