Why Does Pepper Make Us Sneeze?

Black pepper makes you sneeze because it contains piperine, an irritant alkaloid released when peppercorns are crushed or ground. Inhaled piperine activates TRPV1 and TRPA1 receptors on trigeminal nerve endings in the nasal lining, which fire a reflex that ejects the irritant in a forceful sneeze.

As a kid who loved Tom and Jerry, watching Jerry fall into a sneezing fit inside the pepper shaker is a classic, but that obviously brought up a few questions in my head.

I went to the kitchen and tried to make myself sneeze using pepper in the same way (I was a weird kid, I know). To my initial amusement, I sneezed and sneezed… and then sneezed some more. Let me just say, by the time I was finished, it was no longer such a pleasant experience.

If you spend any time in the kitchen, chances are good that this grey-black dust of the peppercorn has likely caused you to sneeze once or twice. Older references will tell you a sneeze races out at a wild 100 miles per hour, but modern high-speed-camera measurements peg the actual peak speed at a far more modest 4–10 m/s (roughly 10–20 mph)—still plenty of force to scatter pepper droplets several feet across the room.

Have you ever wondered what it is about pepper, in particular, that makes us sneeze so readily? What makes pepper so special? There aren’t many spices that have this effect. One spice with a somewhat parallel effect is red chili, which induces a similar sneeze reflex, but there is one difference—it is also accompanied by pain!

Pepper

Peppercorns, whether whole, crushed or powdered, are a commonly used spice in almost every cuisine of the world. The peppercorns we eat are actually fruits of the Piper nigrum plant, part of the Piperaceae family — a flowering vine native to the Western Ghats of southern India (the Malabar Coast of present-day Kerala). Piper nigrum is the most common source of black pepper, and every commercial peppercorn grown today, from Vietnam to Brazil, traces back to those same Indian vines.

Helen of Troy’s face may have launched a thousand ships, but these tiny insignificant-looking red and green balls have, to their credit, launched a few ships in their time too, including the Niña, Pinta and Santa María. Christopher Columbus sailed those ships west in 1492 hoping to reach India and its spice markets (pepper included), and famously ran into the Caribbean instead.

There are many organic compounds present in pepper giving it that typical pungent odor and its tasty properties. Almost 600 compounds have been isolated and identified from black pepper thus far. That’s a whole lot of punch packed into one little peppercorn!

One of these compounds is responsible for triggering the sneeze reflex…

The Culprit – Piperine

The main component of black pepper and the secret to its spicy and pungent qualities is piperine. This alkaloid (an organic compound containing nitrogen) is what makes pepper one of the most widely used spices in the world. The concentration of piperine per peppercorn varies, depending on the strain, typically falling between about 2% and 10% of its dry weight. Naturally, the higher the piperine content, the greater the resulting irritation in the nose, meaning a more intense bout of sneezing.

Piperine specifically engages two ion-channel receptors, TRPV1 and TRPA1, sitting on the trigeminal nerve endings that line the inside of your nose. Once these receptors fire, they kick off a reflex response designed to push the irksome pepper back out.

Sneezing is basically that defensive response — a quick, coordinated blast of air aimed at clearing the irritant from the nasal passage as fast as possible. It is how our noses “scratch themselves from the inside,” so to speak.

Just as dust irritates sensitive noses, it is the finely ground powder of peppercorns that triggers the irritation response. When piperine is locked inside a whole peppercorn, it cannot drift into the nose to reach those receptors. Grinding the peppercorns to a fine dust releases the piperine into the air, and the dust particles physically tickle the mucosa, simultaneously engaging large numbers of trigeminal nerve endings that then induce a sneeze.

Another similar nose aggravator is red chili, with capsaicin as the main culprit. Capsaicin hits the same TRPV1 receptor on the trigeminal nerve, but it does so much more potently and broadly throughout the airway, which is why a face full of chili powder produces not just a sneeze but a sharp, burning pain along with it.

Scientists even exploit this reliable reaction. When researchers need volunteers to sneeze on cue — say, to study how far respiratory droplets travel or to test how well a face mask catches them — they hand the volunteers pepper powder to sniff, a technique known as the pepper stimulus.

If scientists waited for participants to feel a spontaneous sneeze coming on, a single study could take forever. It is much easier to just put some pepper in front of their noses. The volunteers should at least be grateful that the painless option works as well as it does — chili powder would do the job too, but with considerably more screaming.

Conclusion

Pepper is a key part of many recipes, so don’t be surprised if you start sneezing if a recipe calls for some. Just take care not to sneeze into your food—or anyone else’s!

Pepper, no matter how irritating it is when inhaled, is quite delightful on the tongue, so swearing off pepper to avoid its effects is unrealistic.

And if you’re out in public and need to sprinkle some pepper on your food, just be careful not to inhale it. A surprise sneeze across a restaurant table is still one of the great social faux pas (right up there with belching at the dinner table), so aim that pepper grinder downward and breathe through your mouth for a second.