Context: Anxious patients require larger dosage of anaesthetics for induction of anaesthesia which leads to hemodynamic disturbances. Melatonin, as premedication decreases the required dose of induction agent and cause pre-operative anxiolysis.

Aims: To compare effect of oral melatonin with placebo on required induction dose of thiopentone sodium, pre operative anxiety, orientation and sedation.

Materials and Methods: This study was conducted on 80 ASA I & II patients scheduled for surgeries under general anaesthesia. Patients were randomised into two groups to receive melatonin (Group-M) and placebo (Group-P) as premedication. The required dose of thiopentone, anxiety score, sedation score and orientation score were studied at 0 min, 30 min and 60 min. Student t-test has been used to find the significance of study parameters on metric parameters and Mann– Whitney U test was used to find the significance of study parameters on ordinal between two groups.

Results: The mean dose of thiopentone required for SE to reach 50 in group M is 3.69 mg/kg and in group P is 5.46 mg/kg. (p<0.001).The mean dose of thiopentone required for loss of eyelash reflex in group M is 3.56 mg/kg and 5.15 mg/kg in group P. (p <0.001) Patients were less anxious and more sedated at 30 and 60 min of premedication without any change in orientation.

Conclusion: Melatonin 6 mg when compared to placebo given 60 minutes before surgery as a premedicant significantly reduced the induction dose of thiopentone sodium and provided better anxiolysis and sedation without affecting orientation.