Objective. To evaluate the efficacy and safety of Kangfuxin Solution, a pure Chinese herbal medicine, on mucositis induced by chemoradiotherapy in nasopharyngeal carcinoma patients. Methods. A randomized, parallel-group, multicenter clinical study was performed. A total of 240 patients were randomized to receive either Kangfuxin Solution (test group) or compound borax gargle (control group) during chemoradiotherapy. Oral mucositis, upper gastrointestinal mucositis, and oral pain were evaluated by Common Terminology Criteria for Adverse Events (CTCAE) v3.0 and the Verbal Rating Scale (VRS). Results. Of 240 patients enrolled, 215 were eligible for efficacy analysis. Compared with the control group, the incidence and severity of oral mucositis in the test group were significantly reduced (P = 0.01). The time to different grade of oral mucositis occurrence (grade 1, 2, or 3) was longer in test group (P < 0.01), and the accumulated radiation dose was also higher in test group comparing to the control group (P < 0.05). The test group showed lower incidence of oral pain and gastrointestinal mucositis than the control group (P < 0.01). No significant adverse events were observed. Conclusion. Kangfuxin Solution demonstrated its superiority to compound borax gargle on mucositis induced by chemoradiotherapy. Its safety is acceptable for clinical application.