The Actual Research Behind Fart Smell

The smell in farts comes mostly from hydrogen sulfide, a gas your gut bacteria produce when they break down sulfur-containing amino acids in food. A 2016 study from the University of Exeter found that very small amounts of hydrogen sulfide may help your cells produce energy more efficiently and reduce inflammation in the gut lining. This does not mean smelling farts is a treatment — it means the compound itself, in controlled doses, showed activity in lab cells.

The leap from "this molecule does something in a petri dish" to "breathing fart smell is good for you" is where most claims fall apart. Your nose detects hydrogen sulfide at concentrations far below what researchers used in their experiments. The amount you'd actually inhale from a fart is negligible compared to what would be needed to produce any measurable effect in your body.

Most popular claims about fart-smelling benefits come from misreading or oversimplifying this single study. The researchers themselves did not suggest that smelling farts was beneficial — they studied the compound in isolation under laboratory conditions, which is very different from inhaling it from another person's digestive system.

Key Takeaways

  • Hydrogen sulfide, the compound that makes farts smell, has shown some activity in laboratory studies on cells, but this does not translate to health benefits from smelling farts.
  • The concentration of hydrogen sulfide in actual fart smell is far too low to produce the effects seen in controlled lab experiments.
  • No clinical trials have tested whether smelling farts improves human health, reduces inflammation, or prevents disease.
  • Claims about fart-smelling benefits typically misrepresent a single 2016 cell study and ignore the difference between lab conditions and real-world exposure.

Why Lab Results Do Not Equal Real-World Benefits

When researchers study a compound in cells or tissue samples, they use precise, concentrated doses designed to trigger a measurable response. In the 2016 Exeter study, scientists applied hydrogen sulfide directly to cells in a controlled environment. The cells were exposed to specific concentrations for specific periods — conditions you cannot replicate by smelling someone's fart.

Your digestive system produces hydrogen sulfide continuously, but most of it stays in your colon and is either absorbed through the intestinal wall or expelled as gas. The amount that actually reaches your nose when you smell a fart is a tiny fraction of what your body already produces internally. Even if inhaling more hydrogen sulfide were beneficial — which has not been shown in humans — the dose from smelling farts would be far below any therapeutic level.

What the Research Actually Measured

The 2016 University of Exeter study examined how hydrogen sulfide affected mitochondria (the energy-producing structures inside cells) in human cells grown in the laboratory. The researchers found that at certain concentrations, the compound helped cells produce ATP, the molecule cells use for energy, and reduced oxidative stress. This is interesting basic science, but it is not the same as proving the compound helps a living person.

Laboratory studies on isolated cells are the earliest stage of research. They show whether something is worth investigating further, not whether it works in a human body. To move from "this works in cells" to "this helps people," researchers would need to conduct clinical trials — studies in actual humans with proper controls, measurement of outcomes, and accounting for other factors that affect health. No such trials have been done for hydrogen sulfide inhalation from farts.

Potential Risks of Hydrogen Sulfide Exposure

While small amounts of hydrogen sulfide are normal in your gut, breathing in higher concentrations can irritate your respiratory system. Occupational exposure to hydrogen sulfide — in settings like oil refineries or wastewater treatment plants — causes headaches, eye irritation, coughing, and in severe cases, respiratory damage. These effects occur at concentrations much higher than you'd encounter from a fart, but they show that the compound is not harmless at all doses.

People with asthma or other respiratory conditions may be more sensitive to irritants in the air, including hydrogen sulfide. If you have a history of respiratory issues, deliberately exposing yourself to fart smell offers no proven benefit and carries a small risk of irritation.

Where Fart-Smell Claims Come From

The popularity of fart-smell health claims reflects a common pattern: a legitimate scientific finding gets simplified, exaggerated, and spread through social media and wellness blogs until it bears little resemblance to the original research. The 2016 Exeter study was published in a peer-reviewed journal and covered by mainstream media, which helped it spread. But headlines like "Smelling Farts Could Be Good for You" oversimplified the findings and created the false impression that the researchers had tested this in humans.

Once a claim gains traction online, it becomes self-reinforcing. People repeat it, others cite those repetitions as sources, and the original study gets buried under layers of reinterpretation. By the time most people encounter the claim, they have no way to trace it back to the actual research or to see what was lost in translation.

What Hydrogen Sulfide Actually Does in Your Body

Your gut bacteria produce hydrogen sulfide as a normal part of digestion, especially when you eat foods high in sulfur like eggs, meat, and cruciferous vegetables. This gas is one of several compounds your body produces and manages routinely. Some hydrogen sulfide is absorbed through the intestinal wall and used by your cells; the rest is expelled as flatulence or absorbed and exhaled through your lungs.

The fact that your body produces hydrogen sulfide does not mean more of it is better. Many compounds your body makes in small amounts — like cortisol or stomach acid — become harmful at higher concentrations. The dose makes the poison, and the dose also makes the benefit. A compound that helps cells at one concentration may harm them at another.

Frequently Asked Questions

Did the University of Exeter study prove that smelling farts is healthy?

No. The study showed that hydrogen sulfide affected cells in a laboratory dish, not that smelling farts helps people. The researchers did not test fart-smelling in humans and did not claim their findings supported it as a health practice.

Is hydrogen sulfide toxic?

In small amounts, it is a normal part of digestion. At higher concentrations — such as those encountered in industrial settings — it irritates the respiratory system and can cause serious health effects. The amount in a fart is far below toxic levels, but also far below any amount shown to help people.

Could smelling farts help with inflammation?

There is no evidence that it does. While hydrogen sulfide showed anti-inflammatory effects in lab cells, the concentration in fart smell is too low to produce measurable effects in your body. If you have inflammation, evidence-based treatments like exercise, diet changes, and medical care are far more reliable.

What foods make farts smell worse?

Foods high in sulfur — eggs, meat, cruciferous vegetables like broccoli and cabbage, and foods with garlic or onions — produce more hydrogen sulfide when digested. Reducing these foods may reduce fart odor, but this does not affect the health claims, since the amount of hydrogen sulfide is still too low to matter either way.

Should I avoid smelling farts if I have asthma?

If you have asthma or respiratory sensitivity, it is reasonable to avoid unnecessary exposure to any airborne irritant, including fart smell. While the amount in a fart is unlikely to trigger symptoms, there is no benefit to smelling them, so there is no reason to take even a small risk.