Objective There is limited research on the combined use of multiple drugs in the prevention and treatment of radiation-induced oral mucositis (RTOM). This study aims to investigate the synergistic effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF), Kangfuxin Liquid, and vitamin B₁₂ via mouthwash on RTOM, and provide a novel approach for the prevention and treatment of acute RTOM. Methods A total of 82 patients with head and neck cancer who underwent radical radiotherapy were randomly divided into four groups: a control group (vitamin B₁₂, 20 cases), observation group 1 (rhG-CSF + vitamin B₁₂, 20 cases), observation group 2 (Kangfuxin Liquid + vitamin B₁₂, 21 cases), and observation group 3 (rhG-CSF + Kangfuxin Liquid + vitamin B₁₂, 21 cases). After 4 weeks of therapy, the therapeutic effects of the four groups were compared. Results Compared to the control group, there was no statistically significant difference in the incidence of RTOM. However, the incidence of severe RTOM was significantly reduced in the observation groups, following the order of observation group 1 (20.00%) > observation group 2 (14.28%) > observation group 3 (9.52%). The initiation period of RTOM in observation group 3 was 24 days, exhibiting a considerable delay in comparison to the control group (16 days), observation group 1 (18 days), and observation group 2 (22 days). The levels of pain experienced by the groups receiving combined treatments were significantly reduced compared to the control group. Observation group 3 exhibited the most effective pain reduction. Conclusion The combined administration of rhG-CSF, Kangfuxin Liquid, and vitamin B₁₂ can prevent radiation-induced oral mucosal injury and promote mucosal healing. This regimen represents an effective strategy for the prevention and treatment of acute RTOM.