Smoking and IBS

Reviewed by: HU Medical Review Board | Last reviewed: June 2016.

Cigarette smoking harms nearly every organ in the body. Smoking introduces harmful chemicals into the lungs, which are circulated throughout the body. These chemicals can cause disease and have a negative impact on health.1

The most common health problems that cigarette smoking increases are heart disease, stroke, and lung cancer.1 Smoking causes 87% of lung cancer deaths.In the digestive system, smoking has been found to increase the risk of cancers of the mouth, esophagus, stomach and pancreas. Research also suggests that smoking may increase the risk of cancers of the liver, colon and rectum. Cigarette smoking can also increase your risk of developing:

  • Heartburn – A painful, burning condition that occurs when the acid from the stomach backs up into the esophagus
  • Gastroesophageal reflux disease (GERD) – Persistent condition in which the stomach acid backs up into the esophagus causing serious health problems such as bleeding ulcers, narrowing of the esophagus that causes food to get stuck, and cellular changes that can lead to cancer
  • Peptic ulcers – Open sores in the lining of the stomach
  • Crohn’s disease – An inflammatory disease that generally affects the small intestines causing pain and diarrhea; also may include severe symptoms of blockages and ulcers in the intestines
  • Liver disease – The liver filters harmful substances from the body, and some studies show that smoking changes the liver’s ability to process these substances
  • Colon polyps – Growths on the inside lining of the colon or rectum; some may become cancerous
  • Pancreatitis – Inflammation of the pancreas, which causes the digestive enzymes produced by the pancreas to attack the organ, rather than being secreted into the small intestine3,4


Nicotine, the addictive substance in cigarettes, suppresses the immune system and alters a wide range of the system’s normal functions. Nicotine does have a relaxation effect on the smooth muscle in the gastrointestinal tract, and in a study of patients with ulcerative colitis, it was found to reduce the symptoms of frequency and urgency.5 This effect has not been documented in patients with IBS.

The Benefits of Quitting

Quitting smoking has multiple benefits on health. By stopping smoking, the risk of developing smoking-related diseases is lowered and life expectance is increased. The body responds well to quitting: in just 1 year after quitting smoking, the risk of having a heart attack drops sharply, and within 2 to 5 years, the risk of stroke can fall to the same as that of a nonsmoker.1

Positive effects are also seen in the digestive system when smoking is stopped. Within a few hours of a person quitting, the balance between harmful factors and those that protect the stomach and duodenum lining returns to normal. However, there is still an increased risk for developing colon polyps and pancreatitis compared to people who have never smoked.3

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