Smoking is considered to be the most important form among those that harm our health. Nicotine in itself as an additive can build a very strong addiction, but the main health damage is caused by the thousands of chemical components present in the tobacco cigarettes and the smoke, some of them being proven and known carcinogens. It is well known that the risk of lung cancer is at least 16 times higher among smokers, but several other disorders also in the digestive tract have strong connection to smoking. This review tries to collect the most important information regarding upper gastrointestinal disorders like peptic ulcer formation, chronic inflammatory disorders, including inflammatory bowel diseases and diverticulitis, circulatory disturbances and malignant disorders of the gastrointestinal tract. Orv Hetil. 2025; 166(18): 697-703.