Spinal Anesthesia is the most common type of anesthesia provided for various infra-umbilical surgeries. An undesired side effect often seen with the administration of a spinal anaesthetic is hypotension and bradycardia. Current treatments include fluids and vasopressors, with the latter known to have few side effects. The Bezold-Jarisch reflex is the likely cause of hypotension and bradycardia associated with spinal anesthesia¹. This reflex is caused by stimulation of peripheral serotonin receptors 5-hydroxytryptamine (5-HT3 type). Ondansetron is a selective serotonin 5-HT3 receptor² antagonist which may abolish the Bezold-Jarisch reflex response to spinal anesthesia. A knowledge gap exists, stimulating the current study to review on the use of ondansetron to prevent undesired cardiovascular effects of spinal anesthesia. Aim of the study is to study the effectiveness of intravenous ondansetron for prevention of hypotension and bradycardia during spinal anesthesia. Most of the studies conducted till now included caesarean section operation which itself has many factors to cause hypotension such as gravid uterus, blood loss etc. this is the reason we are chosing lower limb surgeris where the confounding factors causing hypotension are less.