Background Some studies had shown that the patients who were continuing smoking after percutaneous coronary intervention (PCI) would increase the incidence of adverse cardiovascular events.American Public Health Service recommended varenicline as the first-line clinical prescription drug for smoking cessation.This study focused on the efficacy of varenicline and the safety of the combination of two drugs by investigating the patients who were given clopidogrel and varenicline with coronary heart disease (CHD) in periprocedure of PCI.