Background: Brain edema induced by radiotherapy is a common complication in patients with brain tumors, for which medical treatment is the treatment of choice. Adjusted-Da-Chai-Ling-Tang, a Chinese herbal formulation, has been confirmed to be protective against the radiation-induced edema. In this study, we investigated the efficiency of adjusted-Da-Chai-Ling-Tang in radiation-induced brain edema in patients with brain tumors. Materials and Methods: A total of 46 patients with brain tumors treated with radiotherapy alone or combined with surgery were enrolled. These patients were divided into two groups: The experimental group with adjusted-Da-Chai-Ling-Tang and the control group with conventional medical treatment. Clinical data including symptoms and serologic results were collected pretreatment and on the 4th, 7th and 10th day posttreatment. Magnetic resonance imaging of the brain was performed to investigate changes in brain edema. Results: Clinical symptoms including headache, dizziness, nausea/vomiting and fatigue significantly improved in the experimental group (P < 0.05). No difference in serological results was observed. Brain edema was significantly reduced in the experimental group in magnetic resonance imaging (P < 0.05). Conclusion: Adjusted-Da-Chai-Ling-Tang is effective in the treatment of radiation-induced brain edema in patients with brain tumors. No obvious side effects were observed.