The average person farts 14 times a day, with a daily exhaust volume of about 0.5 to 2 liters. 99% of the gas has no odor, and farts stink because intestinal bacteria generate sulfur-containing compounds such as hydrogen sulfide. Patricia Raymond, assistant professor of gastroenterology at the Eastern Virginia Medical School in the United States, said that cruciferous vegetables, garlic, onions, cheese, dried fruit, nuts, beer, beans, meat and other foods may lead to fart stink. In addition, smelly farts may also signal certain health risks. 1, lactose intolerance A large percentage of the population lacks the enzymes needed to digest lactose. After ingesting dairy products, lactose is not absorbed through the small intestine and goes directly to the colon. Trillions of intestinal bacteria have an “encounter” with lactose, resulting in smelly farts. In addition, sucrose, fructose and other intolerant people are also prone to smelly farts. 2, sugar alcohols exist in diet drinks, sugar-free candy and some chewing gum, including sorbitol and xylitol. These sweeteners can not be fully absorbed by the body, move down to the colon is easy to generate odor. 3, constipation excessive consumption of low dietary fiber foods will cause defecation difficulties, feces in the colon to stay too long, generating a lot of odor. It is recommended to drink more water, exercise often, eat more high-fiber foods. 4, drugs Certain prescription drugs, vitamins, and iron-containing supplements can cause bloating. Metformin has similar side effects. Another drug used to treat diabetes, alpha-glucosidase inhibitors, can slow down the absorption of carbohydrates, which can also cause an increase in gas. 5, infection or disease If the smelly farts are accompanied by fever, weight loss, blood in the stool, persistent diarrhea and other symptoms, you need to be alert to intestinal obstruction, inflammatory bowel disease, celiac disease, colon cancer.