Irritable Bowel Syndrome (IBS) is the most common functional gastrointestinal disorder, characterized primarily by abdominal pain associated with changes in bowel habits and stool characteristics. The abdominal pain is related to defecation, typically easing after bowel movements. This condition tends to be recurrent and persistent. As for whether individuals with this syndrome can smoke, given that smoking can significantly harm many organs, including the gastrointestinal tract, it is advised against. Smoking can potentially exacerbate the symptoms of Irritable Bowel Syndrome. Therefore, smoking is not recommended for individuals with this condition.