Smoking may adversely affect all parts of an otherwise healthy gastrointestinal (GI) system. Smoking may contribute to acid reflux disease and heartburn because of increased pressure on the passage between the stomach and the esophagus.
Smoking may increase acid secretion and decrease pancreatic secretion, resulting in stomach disorders. Smoking may aggravate or contribute to development of peptic ulcers. If individuals who already have ulcers continue to smoke, the ulcers may never heal.
Smoking may interfere with the liver's functioning. Smoking damages the liver, and so the liver cannot metabolize medications and toxins effectively.
By smoking, an individual may also increase risk of cancer, inflammatory bowel diseases, and Crohn's disease.