Identify environmental factors that can influence the course of inflammatory bowel disease (IBD) is of great interest since managing on these factors might improve the prognosis of patients. No environmental factor has been shown to have a linear cause-and-effect link with the relapse of the disease, but many environmental factors (smoking, diet, medications, stress, etc.) seem to play a plausible role in influencing the clinical course of IBD. The aim of this review is to describe the current evidence of the impact of different environmental factors on the long-term course of IBD and to give practical indications that can help doctors and patients in the management of IBD.