OBJECTIVE： To investigate the effects of mannitol combined with dexamethasone on related indexes of patients with infectious brain edema. METHODS： A total of 120 patients with infectious cerebral edema were divided into control group （60 cases） and observation group （60 cases） according to therapy plan. Control group was given Furosemide injection 20 mg+20％ Mannitol injection 1 g/（kg·time）+0.9％ Sodium chloride injection 10 mL intravenously， every 6 h， 3 days later adjusting drug dose according to the disease condition of patients. Observation group was given Dexamethasone injection 10-20 mg+20％ Mannitol injection 1 g/（kg·time）+ 0.9％ Sodium chloride injection 10 mL intravenously， every 6 h， 3 days later adjusting drug dose according to the disease condition of patients. A treatment course lasted for 7 d， and both groups were treated for 2 courses of treatment.  The levels of NO， IL-1 and TNF-α， mortality and the occurrence of sequelae before and after treatment as well as the occurrence of ADR were observed in 2 groups. RESULTS： Before treatment， there was no statistical significance in the levels of NO， IL-1 or TNF-α between 2 groups （P＞0.05）. After treatment， the levels of NO， IL-1 and TNF-α in 2 groups were significantly lower than before treatment， and the observation group was significantly lower than the control group， with statistical significance （P＜0.05）. The incidence of mortality， sequelae and ADR in observation group were significantly lower than control group， with statistical significance （P＜0.05）. CONCLUSIONS： Mannitol combined with dexamethasone can reduce inflammatory factor level， the incidence of sequelae and mortality， without increasing the incidence of ADR.