OBJECTIVE To compare the efficacy and side effects of hypertronic saline and mannitol use in cerebral edema. METHODS Retrospective study. METHODS Pediatric intensive care unit. METHODS 67 patients with cerebral edema. METHODS Patients with cerebral edema treated with either mannitol or hypertronic saline (HS) (Group II: n = 25), and both mannitol and HS (Group III: n = 20) were evaluated retrospectively. Cerebral edema and increased intracranial pressure were based on the clinical and/or radiological (CT, MR) findings. When treating with both mannitol and HS (Group IIIA), if patients serum osmality was greater than 325 mosmol/L, mannitol was stopped and patients were treated with only HS (Group IIIB). All patients were closely monitored for fever, pulse, blood pressure, central venous pressure (CVP), oxygen saturation, volume of fluid intake and urine output. Mannitol was given at a dose of 0.25-0.5 g/kg while the hypertonic saline was given as 3% saline to maintain the serum-Na within the range of 155-165 mEq/L. RESULTS There was no statistically significant difference in terms of Glasgow coma scale, age, gender, and etiologic distribution between the groups. And also distribution of the other treatments given for cerebral edema is not significiant. Mannitol was given for a total dose of 9.3 +/-5.0 (2-16) doses in Group I, and 6.5 +/-2.8 (2-10) doses in Group III. Hypertonic saline was infused for 4-25 times in Group II. Although there was no statistically significant difference in the highest serum Na and osmolarity levels of the groups, duration of comatose state and mortality rate were significantly lower in Group II and Group III A B. Patients who received only HS were subdivided according to their serum Na concentrations into 2 groups as those between 150-160 mEqL and those between 160-170 mEqL. The duration of comatose state and mortality was not different in patients with serum-Na of 150-160 mEqL and in patients with 160-170 mEqL in the hypertonic saline receiving patients. Four patients in the group II developed hyperchloremic metabolic acidosis and 2 patients in the group I had hypotension. As two patients in group II had diabetes insipidus and one patient had renal failure in group I, the treatment was terminated. The causes of death were septic shock, ventilator associated pneumonia with acute respiratory distress syndrome, progressive cerebral edema and cerebral edema with pulmonary edema. Multivariate analysis showed that age, gender, cause of cerebral edema, electrolyte imbalance, hyperglycemia and hyper-ventilation had no significant impact on outcome. CONCLUSIONS Hypertonic saline seems to be more effective than mannitol in the cerebral edema.