Usually people will have the urge to defecate when they smoke, which is a normal physiological reflex of the human body. This reflex is because cigarettes contain a lot of nicotine and tar, because nicotine can promote metabolism, accelerate the peristalsis of the gastrointestinal tract, so the urge to defecate will occur, so people will have a clinical response to the desire to defecate as soon as they smoke. In addition, after a long period of time, a certain conditioned reflex will be formed when the reaction to defecation occurs after smoking, so many people have the habit of smoking when they go to the toilet, and a natural conditioned reflex and impulse to defecate will be formed more and more when they smoke during defecation for a long period of time. So if many people have the involuntary habit of smoking when they have a bowel movement, this is a non-healthy conditioned reflex that is recommended to be eliminated and avoided as much as possible.