Some people can’t come to the explanation of why their fart smells so bad.

Flatulence is a natural human occurrence and it is considered to be a sign of a healthy digestive tract. The average human being passes between 500 and 1500 milliliters of gas through their rectum daily. That amounts to ten to twenty farts each day.

So why do some farts smell?

1. A major reason farts smell is the consumption of foods that are high in sulphur. Sulphur has an odour of rotten eggs and is notorious for causing foul-smelling farts. Foods high in sulphur include vegetables, meat, eggs, cheese, whole cow’s milk, garlic, onions, and sulfite preserved foods like wine and dried fruits.

2. Intestinal gas is composed of nitrogen, oxygen, carbon dioxide, hydrogen, and methane. These gases are generally odourless, but can become foul-smelling when other gases, such as sulfates, are added. If the gas remains in the intestines for an extended period of time, bacteria start adding foul-smelling sulfates to it.

3. Consumption of foods rich in carbohydrates like potatoes, bread and vegetables are good, but your stomach doesn’t fully digest them. They pass into the small intestine and then the large intestine, which are long tubes leading to your anus. Bacteria break the carbohydrates into smaller pieces and then release gases like hydrogen and carbon dioxide. Those gases don’t smell. But other bacteria in the gut take those odourless chemicals and make them into compounds that do smell.

4. Less commonly, frequent and extremely stinky farts can be a sign of a chronic problem, like irritable bowel syndrome or celiac disease, or an infection like gastroenteritis.

5. According to Dr. Myron Brand, a gastroenterologist at Connecticut Gastroenterology Consultants: “Smelly odour is not bad; it’s just a function of what you’re eating and what bacteria are doing inside your gastrointestinal tract. Everyone is different,” Dr. Brand explains. “Foul smell just means the carbohydrates you consume are being malabsorbed — it’s fermented.”

6. Also, frequent farting that is accompanied by discomfort, bloating, or a very foul odor may indicate a food allergy.


Interestingly, in a study performed at the University of Exeter, researchers found that inhaling small amounts of this gaseous compound had protective properties against damage of cell mitochondria and even against cancer. The mitochondria is the “powerhouse” of cells.

Furthermore, smelly farts might not be as bad as you think, and regular farting could also be a sign that you’re consuming enough fiber, and have a healthy collection of bacteria in your intestines.