CIGARETTES FOR CONSTIPATION. “Nicotine acts on receptors in the bowel wall to speed up contractions that moves food through the gut. Similarly, it can affect the major pushing movements that characterize the defecation process. Naturally when you quit smoking the process is slightly disturbed from what you were accustomed to.”
http://www.neednicotine.com/constipation-and-altered-bowel-habit-after-quitting-cigarettes/