A 2010 survey showed that 77.5% of Chinese people knew that smoking causes lung cancer. This means that most people are more or less aware of the dangers of smoking to the respiratory system, but many are unaware of what other health risks it can cause and how serious those dangers really are. In fact, the damage caused by smoking is systemic, as the harmful substances in tobacco smoke can enter the body through the mucous membrane of the respiratory tract, causing adverse effects in almost all tissues and organs of the body, and then endangering human health. The human digestive system is especially hard hit by tobacco poisoning. Although the most popular way of smoking cigarettes does not make the smoke directly into the digestive tract, but the harmful substances in the smoke are absorbed into the body through the mucous membrane of the nose and mouth and respiratory tract, and can enter the digestive tract through the circulatory system, thus causing various toxic effects on the human digestive system. Smoking can cause a variety of digestive system tumors There is sufficient evidence that tobacco can cause digestive system cancers such as esophageal cancer, stomach cancer, liver cancer and pancreatic cancer. Although the evidence that smoking causes colorectal cancer is not as strong as the previous cancers, studies have shown that smokers have a significantly higher risk of developing colorectal cancer than nonsmokers. Most of these smoking-caused cancers have very distinctive features, namely: 1. there is a significant correlation between smoking behavior and the development of cancer; 2. the greater the amount of tobacco smoked and the longer the number of years smoked by smokers, the higher the risk of developing cancer; and 3. quitting smoking reduces the risk of developing cancer. These characteristics suggest a close relationship between smoking and these malignancies, the longer the total time of exposure to tobacco and the greater the amount of smoking, then the greater the risk of developing cancer. Not only does first-hand smoke from smokers cause cancer, but non-smokers who inhale second-hand smoke also have an increased risk of developing cancer. Smoking increases the risk of H. pylori infection H. pylori is a bacterium that resides mainly in the human stomach and has been shown to be associated with chronic atrophic gastritis, gastric and duodenal ulcers, gastric cancer, mucosal tissue-associated lymphoma of the stomach, and many other stomach diseases. And smoking can increase the risk of HP infection in patients. Some individual studies suggest that smokers who smoke ≥20 cigarettes per day have a 33% higher risk of HP infection than nonsmokers. This is not because smokers are more exposed to the source of HP infection, but probably because nicotine decreases blood flow to the gastric vessels and subsequently decreases the stomach’s ability to resist HP infection. Not only does tobacco increase the risk of H. pylori, but among patients who are already infected, the risk of developing gastric or duodenal ulcers is much greater in smokers than in nonsmokers. This suggests that H. pylori infection and smoking may play a 1+1>2 role in the pathogenesis of gastric and duodenal ulcers. That is, the risk of HP infection and smoking on the development of the disease in patients is not simply superimposed, but the two harmful factors may contribute to each other and increase their respective harms. Of course, more research is needed to confirm this. However, there is no doubt that smoking clearly increases the risk of patients suffering from HP infection, which in turn increases their risk of many digestive diseases caused by HP infection. Gastroenterology reminds us that there is ample evidence that tobacco can cause digestive cancers such as esophageal, stomach, liver and pancreatic cancers, so please try to smoke less for your health and that of your family.