There is some truth in it. Here is what makes wind smell, and why the loud ones are often less smelly.
What wind is made of
Most of the gas we pass has no smell. It is mainly nitrogen and oxygen from swallowed air, and carbon dioxide, hydrogen and sometimes methane made by bacteria in the bowel. The smell comes from tiny amounts of sulphur gases, such as hydrogen sulphide, the “rotten egg” gas.
Loud or silent
The sound depends on how much gas there is, how fast it leaves, and how tight the muscle of the anus is. Loud wind is often a larger volume of gas, much of it swallowed air, which has little smell. Silent wind is often a smaller amount released slowly, and more of it may be gas from bacterial fermentation, which carries the sulphur. So a silent one can be smellier, but not always.
The make-up of the gas may also change the sound. Wind with more hydrogen, a very light gas, is likely to be less smelly, and lighter gas tends to give a higher-pitched sound, in the same way that breathing in helium raises the voice. Our ears are more sensitive to higher pitches, so this kind of wind may seem louder.
What makes wind smell more
- Foods rich in sulphur: eggs, meat, cabbage, broccoli, cauliflower, onions and garlic
- Beer and some supplements
- Constipation, as stool sits longer in the bowel
- Gut infections, and conditions where food is not absorbed well, such as lactose intolerance
Smelly wind on its own is normal. See a doctor if it comes with diarrhoea, greasy stools that are hard to flush, weight loss, or blood in the stool. See also why do I pass so much wind?
General information only. Reviewed by Dr Chia Chung King, 2026-11-13. Book a consultation.