It should be said that smoking at any time is inappropriate, smoking is harmful, not only to the respiratory system, but also affect the heart, blood vessels and digestive system, easily cause chronic inflammation, will aggravate atherosclerosis, aggravate coronary heart disease, but also induce stomach cancer and lung cancer, it is best to quit smoking. If you have to smoke, you can smoke two hours after meals, when most of the food is digested, can reduce the impact of smoking on the digestive system, but can not completely avoid the impact, will affect the absorption of nutrients, the stomach and duodenal mucosa will also have direct damage, but also easy to cause gastrointestinal tract disorders, so it is best to quit smoking.