The fart odor is caused by hydrogen sulfide, a substance that causes a foul smell, If you have a lot of starch in your food, it is easy to produce more exhaust, which will also have some bad smell. 3, indeed, there are some diseases in the intestinal tract, such as suffering from colorectal cancer, which will also produce some intestinal harmful bacteria, these bacteria, if the decomposition of food is not timely enough, will also produce more hydrogen sulfide, which will produce a more smelly fart. If the farts are still stinky after diet adjustment, even with pus and mucus, abdominal pain, weight loss, etc., you must go to the hospital for consultation and, if necessary, colonoscopy to rule out organic colon disease.