Inflammatory bowel disease(IBD) is a chronic condition with a pathogenic background that involves both genetic and environmental factors.Although important progress has been made regarding the former in the last decade,scarce knowledge is available for the latter.In this sense,smoking remains the most important environmental factor in IBD.Active smoking increases the risk of developing Crohn’s disease(CD).Moreover,CD patients who start or continue smoking after disease diagnosis are at risk for poorer outcomes such as higher therapeutic requirements and disease-related complications,as compared to those patients who quit smoking or who never smoked.However,the harmful effect of active smoking is not uniform in all patients or in all clinical scenarios.Interventions designed to facilitate smoking cessation may impact the course of the disease.In this article,the available evidence of the deleterious effects of smoking on CD is reviewed in detail,and alternative therapeutic approaches to CD in smokers are proposed. Inflammatory bowel disease (IBD) is a chronic condition with a pathogenic background that involves both genetic and environmental factors. Although important progress has been made regarding the former in the last decade, scarce knowledge is available for the latter. the most important environmental factor in IBD. Active smoking increases the risk of developing Crohn’s disease (CD). Moreover, CD patients who start or continue smoking after disease diagnosis are at risk for poorer outcomes such as higher therapeutic requirements and disease-related complications, as compared to those patients who quit smoking or who never smoked.However, the harmful effect of active smoking is not uniform in all patients or in all clinical scenarios.Interventions designed to facilitate smoking cessation may impact the course of the disease. In this article , the available evidence of the deleterious effects of smoking on CD is reviewed in detail, and alternative therapeutic approaches to CD in smokers are proposed.