Smelling farts may have some surprising health benefits, though the research is still limited
Farts contain hydrogen sulfide, a gas that your body produces naturally during digestion. While the smell is unpleasant, some research suggests that exposure to small amounts of hydrogen sulfide might reduce inflammation, improve blood vessel function, and protect cells from damage. A 2016 study at the University of Exeter found that cells exposed to hydrogen sulfide showed improved mitochondrial function — the part of the cell that produces energy. This does not mean you should deliberately smell farts for health reasons, but it does suggest the gas itself is not purely harmful at low concentrations.
The key distinction is between the gas itself and the experience of smelling it. Hydrogen sulfide at very high concentrations is toxic, but the tiny amounts in farts are far below dangerous levels. Your nose detects these gases at extremely low thresholds, which is why farts smell so strong even though the actual amount of hydrogen sulfide is minimal.
Key Takeaways
- Hydrogen sulfide, the main compound that makes farts smell, may have anti-inflammatory and cell-protective effects at low concentrations.
- A 2016 University of Exeter study found that cells exposed to hydrogen sulfide showed improved energy production in mitochondria.
- The amount of hydrogen sulfide in a fart is far too small to cause harm, even though your nose can detect it easily.
- Current research is preliminary, and deliberately exposing yourself to farts is not a proven health strategy.
How hydrogen sulfide affects cells
Hydrogen sulfide is produced by bacteria in your colon as they break down food, particularly sulfur-containing amino acids from proteins. Your body also makes small amounts of hydrogen sulfide naturally in your tissues, where it appears to play a role in reducing inflammation and protecting blood vessels.
When researchers exposed human cells to low doses of hydrogen sulfide in laboratory settings, the cells showed signs of reduced oxidative stress — a condition where cells accumulate damage from unstable molecules called free radicals. The gas appeared to help cells maintain their energy-producing structures, which could theoretically slow aging and reduce disease risk. However, these are laboratory findings, not proof that breathing farts provides these benefits in real life.
The difference between laboratory findings and real-world exposure
Laboratory studies can show what a substance does to cells in a controlled environment, but that does not automatically mean the same effect happens in your body when you encounter it naturally. In the Exeter study, researchers applied hydrogen sulfide directly to isolated cells — a very different scenario from inhaling trace amounts of gas from a fart.
Additionally, your body already produces hydrogen sulfide internally, so you are not gaining something entirely new by smelling farts. The question of whether the additional exposure from farts provides any measurable benefit remains unanswered. No human studies have compared health outcomes between people who are regularly exposed to farts and those who are not.
Why hydrogen sulfide is not dangerous at fart concentrations
Hydrogen sulfide becomes toxic at high concentrations — exposure to 100 parts per million or higher can cause serious health problems. A single fart contains hydrogen sulfide at concentrations far below this threshold, typically in the range of a few parts per million or less. Your nose is extraordinarily sensitive to this gas, which is why even tiny amounts produce a noticeable smell.
This sensitivity actually serves a purpose: it alerts you to the presence of the gas without any risk of harm. The unpleasantness of the smell is not a sign of danger — it is straightforward your nose's way of detecting a compound at extremely low levels.
What other gases are in farts
Farts are not pure hydrogen sulfide. They contain nitrogen, oxygen, carbon dioxide, methane, and hydrogen, along with trace amounts of hydrogen sulfide and other sulfur compounds. Methane and hydrogen are odorless; the smell comes almost entirely from hydrogen sulfide and related sulfur compounds, which make up less than 1 percent of the gas by volume.
The composition of farts varies based on diet, gut bacteria, and individual digestion. People who eat more sulfur-containing foods — like cruciferous vegetables, eggs, and meat — tend to produce farts with higher hydrogen sulfide concentrations and stronger smells.
Current research limitations and what scientists still do not know
The research on hydrogen sulfide and health is still in early stages. Most studies have been conducted in laboratory settings or in animals, not humans. While the Exeter findings were interesting, they did not establish that smelling farts improves health in any measurable way.
Scientists do not yet know whether the hydrogen sulfide your body produces internally is sufficient for any health benefits, or whether additional exposure from external sources would add value. They also do not know whether the other compounds in farts might offset any potential benefits of hydrogen sulfide. More human research would be needed to answer these questions.
Why people are interested in this topic
Interest in the potential health benefits of hydrogen sulfide has grown partly because of broader research into how the body uses gases like nitric oxide and carbon monoxide for cell signaling. Scientists have discovered that these gases play important roles in health, which led researchers to investigate whether hydrogen sulfide might work similarly.
The topic also appeals to people because it offers a humorous angle on wellness — the idea that something universally considered unpleasant might actually be good for you. This has led to some exaggeration in popular media, where preliminary laboratory findings have sometimes been presented as proof that smelling farts is beneficial.
Frequently Asked Questions
Is it actually healthy to smell farts?
The research suggests hydrogen sulfide may have protective effects on cells, but this has only been shown in laboratory settings. No human studies have demonstrated that smelling farts improves health. Your body already produces hydrogen sulfide internally, so any additional exposure from farts is likely minimal.
Can hydrogen sulfide be toxic?
Yes, but only at much higher concentrations than what you encounter in a fart. Hydrogen sulfide becomes dangerous at 100 parts per million or higher. A fart contains far less than this, so there is no toxicity risk from normal exposure.
What causes the smell of farts?
Hydrogen sulfide and other sulfur compounds are responsible for the smell. These make up less than 1 percent of the gas in a fart, but your nose can detect them at extremely low levels. The rest of a fart is mostly nitrogen, oxygen, carbon dioxide, methane, and hydrogen.
Do all farts have the same composition?
No. Diet, gut bacteria, and individual digestion affect what gases are produced. People who eat more sulfur-containing foods like eggs, meat, and cruciferous vegetables tend to produce farts with stronger smells and higher hydrogen sulfide concentrations.
Should I deliberately try to smell farts for health reasons?
There is no scientific reason to do so. While hydrogen sulfide may have some protective effects on cells, your body already produces it naturally. Current research does not support deliberately exposing yourself to farts as a health strategy.