Post Operative Nausea and Vomiting (PONV) is a major distressing problem not only for the patients but also for the treating medical team.PONV can complicate in many ways such as Aspiration Pneumonia due to aspiration of gastric contents ,Boerhaeve syndrome due to dehiscence of walls of esophagus during retching associated with severe PONV, secondary and tertiary complications due to scar rupture.The present study is conducted on 5-HT3 antagonists Ondansetron and Palonosetron,which are good anti emetics.Palonosetron has strong 5-HT3 antagonising action due to its allosteric modulation at the receptor site and has got long t1/2 also.Hence this study mainly focussed on prevention of PONV and its complications in patients undergoing surgery under general anesthesia with a good anti emetic property and better safety profile.