Shivering is one of the most common complications of a central neuraxial blockade, due to impairment of the thermoregulatory control. It has been reported in 40 to 70% of patients undergoing surgery under regional anesthesia. Shivering, an oscillatory, involuntary muscular activity, is a physiological response to core hypothermia in an attempt to raise the metabolic heat production. Prolonged impairment of thermoregulatory autonomic control under anaesthesia along with the cold environment of operating rooms and cold infusion fluids, contributes to a fall in core body temperature, and hence shivering. It  increases the oxygen consumption considerably  and is uncomfortable and  distressing to the patient, anaesthesiologist, as well as to the surgeon. Shivering also increases intraocular and intracranial pressure, and may contribute to increased wound pain, delayed wound healing and delayed discharge from post-anaesthetic care unit. So, apart from being an uncomfortable experience, its deleterious effects warrant primary prevention and prompt control. This study is designed to evaluate the efficacy of intravenous Pethidine, Butorphanol, Dexmedetomidine for treatment of shivering under spinal anaesthesia. This is a randomized prospective study and will be conducted in 150 patients of both genders with age between 18-60 years, ASA I, II & III who develop shivering under spinal anaesthesia during various orthopaedic, inguinal, abdominal, gynaecological procedures. Cases will be randomly divided into 3 groups (Group P, B & D) with 50 patients in each group. Group P will receive injection pethidine 0.5 mg/kg intravenously, Group B will receive injection butorphanol  0.02 mg/kg intravenously and Group D will receive 0.5 µg/kg of injection dexmedetomidine intravenously as soon as shivering is encountered after induction of spinal anaesthesia. The time of induction of spinal anaesthesia will be noted, grading of  the shivering will be done , time of onset of shivering, time at which study drug is given and time at which shivering ceases will be noted. We will also note axillary temperature at the time of onset of shivering and and at cessation of shivering . Patients will also be observed intraoperatively for any variations in hemodyanamic parameters (heart rate, systolic and diastolic blood pressure, oxygen saturation ,respiratory rate).We will also take a note of any recurrent episode of shivering and incidence of adverse effects like hypotension, bradycardia, nausea, vomiting, dizziness, somnolence, among the groups.