Objective To investigate the effects of ozone treatment and drug therapy on the extent of brain edema and plasma level of endothelin among postoperative brain tumor patients.Methods Sixty postoperative patients with cerebral hemisphere brain tumors were randomly divided into two groups: drug therapy group (n=30) and ozone treatment group.(n=30). The extent of brain edema and plasma level of endothelin were determined before and after treatment.Results No significant difference in extent of brain edema or plasma level of endothelin was observed between the two groups before surgery (P>0.05). After surgery, the ozone treatment group showed significantly higher reductions in plasma level of endothelin and extent of brain edema compared with the control group (P<0.01).Conclusions Compared with drug therapy, ozone treatment shows a better performance in reducing the extent of brain edema and plasma level of endothelin, and thus benefits patients by promoting postoperative functional recovery and improving quality of life.