Stroke is the leading cause of mortality world wide. The most common complications of mannitol therapy are fluid and electrolyte imbalances. In the present study 25 patients of stroke and 25 healthy individuals were taken as controls. Serum sodium and Serum potas-sium were estimated by flame photometer. Hyponatremia was seen on first day of admis-sion before giving mannitol as compared to controls. After infusion of mannitol till third day no electrolyte imbalances were noted. Results suggest that mannitol can be safely given to patients as there were no complications of electrolyte imbalances till third day.