Once applied, these recommendations identified hypotonic fluid as the ideal maintenance fluid choice in hospitalized children, leading to the widespread use of 0.225% and 0.45% saline in this population. However, the widely used recommendations of Holliday and Segar did not consider the changing fluid and electrolyte requirements of a sick or postoperative child. Hypotonic fluid with a low sodium content (77 meq/l) and high percentage of electrolyte free water (78% EFW) can cause dilutional hyponatremia.Along with this, non-osmotic stimuli of anti-diuretic hormone (ADH) secretion in postoperative period makes the patient more vulnerable to hyponatremia. The primary stimulus for ADH release is an increase in osmolality however, many non-osmotic stimuli like nausea have also been identified as a potent non-osmotic stimulus for ADH release.Non osmotic causes of ADH release are broadly divided into hemodynamic and non-hemodynamic stimuli for its release. Hypovolemia, hypotension, hypoalbuminemia, congenital heart failure are some hemodynamic causes of non-osmotic secretion of ADH. Pneumonia, bronchitis, hypoxia, meningitis and brain tumour are some of the non-hemodynamic causes of ADH release.