Asking for a friend: What causes really smelly farts? (And how can “she” fix it?)

As the lifestyle guru Shrek once said, “Better out than in.” But seriously, the gastroenterologist I spoke with this morning invoked the green ogre’s words of wisdom about farts. Now, we all know everybody gets a little gassy now and then. But depending on what you’ve had to eat, everyday flatulence (that’s the fancy word for farts) ranges from the mildly stinky to the hideously fetid.

“Basically, the first thing to remember is that all flatulence will have a certain amount of odor,” says gastroenterologist Niket Sonpal, MD. Our bodies cannot digest certain materials— compounds like cellulose,  high-fiber foods, starches in vegetable products (particularly of the cruciferous variety, like cauliflower and broccoli), meat products, and artificial sugars found in diet sodas or coffee sweeteners. “Sometimes a lot of these products can’t be full digested,” he says, “and this gives rise to something called hydrocarbons.” Hydrocarbons (another technical term for “gas”) have to exit your body somehow…so they do.

The two categories of gas—or “flatulence”

Dr. Sonpal says it can be useful to think of gas in two categories: normal (you know, quotidian farts) and smellier than usual. “Now if it’s a one-time, room-clearing kind of fart, then that could be usually related to something. It could be a touch of food-poisoning or enteritis,” says Sonpal. In other words, make like Shrek and foster a little bit of self-acceptance toward your flatulence. Or you can cut down on the cruciferous veggies and coffee creamer, if you so choose.

So what if your farts’ smell is becoming a regular issue?

“When it becomes the kind where it’s noticeable, extremely overwhelming, or what we call essentially foul-smelling, that’s when we have to start wondering, ‘Okay, is this a one-time thing or is it becoming chronic?'” If the latter part of that question sounds like your experience with farts, it’s time to book an appointment with your physician or gastroenterologist to check in on the state of your microbiome. “As a gastroenterologist, I become concerned,” says Sonpal. “And the first thing I start to worry about is infections, your diet, and then what is the overall state of what we call your gut microbiome.”

For example, people who suffer from celiac disease may emit a more noxious brand because their bodies experience malabsorption of certain foods, says the doctor. “It sits in the colon, it sits in the small intestine and so it rots like anything else. So what you’re smelling is actually rotten food,” he says. For some, even after removing gluten from their diets, the intestinal lining might have trouble absorbing other foods. Since only 1 percent of the population has celiac disease, though, such cases are rare.

“Better out than in.” —Niket Sonpal, MD, gastroenterologist

And…what if your gas only visits on occasion? Like a super-annoying relative?

If you just experience the occasional gas-attack, you could abstain from cauliflower pizza and say farewell to artificial sweeteners. But what kind of life is that, I ask you? A world without Brussels sprouts doesn’t sound like a world I want to be a part of. If you agree, crack a window, light a non-toxic candle, and just deal with it.

This post was originally published February 19, 2019. Updated August 27, 2019.

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