How does smoking affect bowel movements? In more ways than you could imagine.

Though smoking does not cause diarrhea or constipation, it does have other effects on your poop.

Colon Cancer

“Smoking is a risk factor for the development of colon cancer,” says Benjamin Levy, MD, board certified gastroenterologist who provides clinical care to patients at Mount Sinai Hospital, Schwab Rehabilitation Hospital, and Sinai Medical Group Touhy Refugee Clinic.

And colon cancer can change the appearance of bowel movements as well as the mechanics.

Symptoms of colon cancer include:

  • skinny long stools or ribbon-like stools
  • going more than three days without a BM
  • feeling like you still have a lot of BM to void even though you just voided
  • abdominal or back pain
  • nausea
  • unexplained weight loss and unexplained fatigue.

“Fortunately, there are many ways to quit smoking such as nicotine patches, nicotine gum and a medication named Chantix (varenicline),” says Dr. Levy.

And if you have never smoked, don’t start! Nobody later on in life regrets never having tried a cigarette in their youth. Nobody.

Smoking’s Direct Impact on BM’s

“It’s true that nicotine can stimulate the colon, contribute to loose bowel movements and cause abdominal cramping,” says Dr. Levy.

“It’s also known to worsen IBS (irritable bowel syndrome) symptoms, in addition to the symptoms of Crohn’s disease.

“Smoking can also exacerbate heartburn and can put patients at additional risk for developing ulcers in the stomach and the small bowel.”

The blood from an ulcer can make its way to one’s poop, creating the frightening discovery of blood in one’s feces.

“In very rare cases, patients who smoke excessively can experience loose bowel movements if they develop a condition called pancreatic exocrine insufficiency – when the pancreas isn’t able to properly digest fats and protein.

“Interestingly, a 2017 study published in the journal Pancreas showed that in certain patients, smoking may be worse for pancreatic function than alcohol abuse.”

Smoking does not affect the odor of stools nor does this expensive habit change their color (e.g., dark brown, medium brown, greenish, greyish).