Chili peppers burn your butt: Making sense of "duh" discoveries


With a title like "Red Hot Chilli Consumption Is Harmful in Patients Operated for Anal Fissure—A Randomized, Double-Blind, Controlled Study", you know you're in for a wild ride.

Yes, doctors in India really did take two groups of patients scheduled for a sphincterotomy (explanation linked, rather than described here, as a courtesy to those of you currently on lunch break) and randomly assign one group to receive 1.5 grams of dried chili powder twice a day, while the other got a placebo. And—perhaps unsurprisingly—it turned out that ingesting 3 daily grams of chili powder makes an already painful anal area even more uncomfortable.

But why—aside from some sort of perverse sadistic streak—would anyone conduct such a study? (And, more importantly, why the hell would anyone sign up to be one of the research subjects?) What seems like a pointless waste of time and money makes a lot more sense when you consider culture.

Indian food, as you may have noticed, is generally on the spicy side. Cutting peppers out of your diet in Mumbai is more of a challenge than in, say, Peoria. So, even though everybody pretty much already agreed—anecdotally—that hot peppers were a bad thing for anal-fissure patients, the researchers wanted some hard cause-and-effect proof that the relatively big lifestyle change those patients were being told to make was actually worth making. Even the amount of chili powder the subjects received was modeled to mimic the amount eaten by an average Indian at lunch and dinner.

My point: Sometimes, "stupid" studies really do have a point—one that's easy to miss if you're too tightly focused on "common sense". Besides, if it weren't for research like this, we'd all miss out on such fabulously titled graphs as "Effect of chili consumption and placebo on anal burning in the first 7 days after sphincterotomy". Small price to pay, really.

Full text of paper from the journal Digestive Surgery

(Thanks to Nat Torkington for tipping me off to the existence of this paper.)

Image courtesy Flickr user my_world_perspective, via CC



  1. It annoys me when people write a study off due to its conclusions being “common sense” – whatever that is.

  2. Why, oh why, did I click the link? My cherry pastry suddenly doesn’t look so good.

  3. I wonder what they used as a placebo? I know I can tell the difference between the mild and hot salsa, and I suspect I’m not the only one!

    1. The complete article says they used opaque pill capsules that contained either “1.5g of chili powder and 0.5g of microcrystalline cellulose” (experimental condition) or “2g of microcrystalline cellulose” (control condition). Presumably both taste the same going down.

  4. There is no such thing as an obvious study. They’re all useful. There have been so many things in the past that have been assumed to be true because of folk history or “common sense” that it does us good to study these things, because on the odd occasion common sense is incorrect we often learn something valuable.

    1. If there’s no double blind study to cite, the commentariat will cry that it can’t be possibly be true. If a study proves it true, they cry that it’s obvious and a waste of money and probably part of a conspiracy by the other political party. It has nothing to do with science. People are just cranky.

  5. Maybe this isn’t as obvious as it seems. After all, capsaicin is known to relieve pain by overwhelming nerves and it’s not that far-fetched to suppose it might do so at a surgical site.

  6. I wonder if anal burning is in any way related to anal leakage.

    Glaah. Now I wonder why I wondered that.

  7. I just saw one of those “duh” discoveries on the “captivate” screen in the elevator:
    Using normal kitchen spoons leads to medicine mis-dosing. Really?!
    As if the recommended dosage could ever be right for each person’s weight, metabolism, immune system, etc.
    I wonder how much that useless info cost to obtain.

  8. if a study reinforces common sense, people mock the scientists.

    if a study overturns common sense, it’s a hot topic for a long time.

    i’ve always thought that a percentage of “duh” studies serve as building blocks for other, perhaps more complex studies that need reliable data on these subjects, not just assumptions. even where they aren’t a foundation, having good data on anything is better than anecdotal or received wisdom.

  9. I am a big supporter of taking a scientific look at what may seem to be common sense phenomena. The ancient Greeks believed that everything could be figured out simply by using logical thought. Experimentation was not even considered.
    That way of thinking held sway up through the Dark Ages, during which time everybody naturally believed (as I did when I was five) that heavier things fell faster than light objects. Nobody disagreed because nobody checked. Then Gallileo came along and challenged everyone’s beliefs by actually watching things as they fell, and the scientific method was born.
    It’s a good approach, and one that is often dissed by people who are uncomfortable with science. Common sense is great, but for important ideas – ideas that major decisions and policies are based on, it’s important to get your facts right from the beginning.
    It’s surprising how many medical decisions are based on conclusions which start out as common sense, and then turn out to be wrong on further study.
    As a rather benign example, take the belief that emergency rooms are more active on nights with a full moon. Everybody in a hospital seems to think that’s the truth, so a friend of mine set out to study it. He looked at the number, and severity of ER visits on nights with a full moon, compared with nights without. (All other factors: day of the week, weather, etc.. were the same). No difference. The funny thing is, people still think full moons make the ER busier. Human belief is way stronger than fact.

  10. How is it a “duh”?

    1) Capsaicin is used as a pain reliever

    2) I eat spicy food all the time. My chili is probably considered toxic waste in several states (6-7 habeneros in about 3 quarts, plus more of other peppers). I have yet to have “burning ring of fire”.

  11. My parents are Indian, and it IS a HUGE deal to give up chili. When you’re conditioned to add chili to everything, it’s a pain *haha, pun* to give it up. It’s like saying not to add salt to your food. See how well that worked for high blood pressure in the U.S.? Yea.

    But it’s not like Indians don’t know it burns. (Well, I don’t, but my family always warns me about eating food that’s too spicy. Maybe I’ll feel it when I’m older.) However, for some folks, even the scientific method will not convince people to stop doing what they’re doing. But, at least there’s one less excuse to resist change.

  12. I remember hearing Dr Karl say that chilli’s only burn once. I lost my faith in Dr Karl that day.

  13. Well, I live in Peoria, and there’s plenty of chili pepper in my diet. I’m just sayin’.

  14. That’s funny. I once had a patient tell me, in all seriousness, that there are no studies that show a causal link between cigarette smoking and lung cancer.
    That’s absolute BS, but I certainly was respectful in how I corrected him. Still, I’m sure he’s somewhere smoking a cigarette right now. People are going to believe what they’re going to believe, and all the facts in the world will not convince them otherwise.

    1. Not all people. Yes, there are people who believe what they want to believe but most intelligent people are ready to admit where they’ve been wrong and try to correct their opinions on matter when presented with proper evidence on the subject.

  15. Dagnabbit – where can I get my hands of some of this study money? I have a whole bunch of unanswered questions. Does tickeling skunks make you smellier? Does driving while eating fast food or driving while texting cause more accidents? What are the range and cost of injuries sustained by a married man from answering the questions “Do these pants make me look fat?” incorrectly?

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