Oral mucositis (OM) is an acute side effect of radiotherapy for head and neck cancer (HNC). OM associated pain affects oral functions and nutrition of the patient that may result in discontinuity of treatment.The purpose of this clinical study is to evaluate the therapeutic effects of Compound Kushen Injection (CKI) on oral mucositis caused by radiotherapy of head and neck cancer.

Patients with oral mucositis caused by radiotherapy for Head and Neck Cancer，will be enrolled in the trial, then seprated randomly in two group,the experimental group treated with Levofloxacin injection plus CKI; the contral group treated with Levofloxacin injection only. Clinical grade of radioactive oral mucositis，Oral pain score，Completion and duration of interruption of radiotherapy， Completion of chemotherapy during concurrent chemoradiotherapy，weight change，Food intake (liquid food, semi liquid food)，recovery time of oral mucositis will be compared before treatment, 3 days, 5 days and 7 days after treatment between the experimental group and the control group.

Inclusion Criteria:

1. Patients are pathologically diagnosed as stage III or stage Ⅳ squamous cell carcinoma of head and neck cancer (including nasopharyngeal carcinoma)and are in accordance with the diagnostic criteria of radiotherapy induced mucositis/ stomatitis;
2. Patients have no prior history of radiotherapy, and grade III oropharyngeal mucositis occured after the first radiotherapy;
3. Patients have no stomatological diseases such as ulcer, edema and exudation in the oropharyngeal mucosa before radiotherapy;
4. Eastern Cooperative Oncology Group (ECOG) performance Score is 0 or 1;
5. The function of each organ is basically normal, including: hemoglobins ≥ 9g/dL, platelets ≥ 80×10^9/L, leukocytes ≥ 3×10^9/L, liver function within 3 times the upper normal limit, creatinine clearance ≥ 60mL/min;
6. Patients aged between 18 and 75 years;
7. Patients have a life expectancy of at least 6 months;
8. Patients have fully understood the study and signed the informed consent voluntarily prior to any related procedures of the study.

Exclusion Criteria:

1. Patients who have received CoKS or systemic antibiotic treatment within 2 weeks before treatment;
2. Patients who have a history of head or neck surgery (except biopsy);
3. Female patients who are pregnant or breast feeding or female of pregnancy potential with a positive pregnancy test before treatment;
4. Patients with serious or uncontrolled organic diseases or infections, such as decompensate cardiac function failure, pulmonary function failure, liver function failure, renal function failure, causing unability to tolerate radiotherapy;
5. Patients who have radiotherapy contraindications;
6. Patients who are allergic to the study medications or quinolones;
7. Patients have serious psychological or psychiatric disorders, drug abuse or alcohol dependence in the past;
8. Patients are currently participating in another clinical study or have participated in another clinical trial in the past 30 days;
9. The investigator believes that it is not appropriate to participate in this trial.