OBJECTIVE： To investigate the effects of Kouyanqing granules on prevention and treatment of radiation-induced oral mucositis patients with head and neck cancer after radiotherapy. METHODS：A total of 122 head and neck cancer patients receiving radiotherapy were randomly divided into kouyanqing group （61 cases） and chlorhexidine group （61 cases）. Based on radiotherapy， kouyanqing group was given Kouyanqing granules 20 g dissolved in 50 mL lukewarm boiled water， twice a day， 2-3 d before radiotherapy. Chlorhexidine group was given Compound chlorhexidine gargle 10-20 mL， twice a day， 2-3 d before radiotherapy. Treatment courses of 2 groups lasted for 7 weeks. The occurrence of oral mucositis， VAS scores and ADR were observed in 2 groups. RESULTS： 3rd week radiotherapy later，the incidence of oral mucositis at level 2-3 and 4th-7th week radiotherapy later， the incidence of oral mucositis at level 2-4 in kouyanqing group was significantly lower than chlorhexidine group， with statistical significance （P＜0.01）. 2nd-7th week radiotherapy later， VAS score of kouyanqing group was significantly lower than that of chlorhexidine group， with statistical significance （P＜0.01）. There was no statistical significance in the incidence of ADR between 2 groups （P＞0.05）. CONCLUSIONS： Kouyanqing granules can relieve radiation-induced oral mucositis of head and neck cancer and the degree of pain，and improve the quality of life. Its safety is similar to that of chlorhexidine.