Hot sauces, curries, wasabi peas and other spicy treats turn you into a snot faucet. Why is that?
Capsaicin is the chemical found concentrated in the placental tissue of chile peppers and allyl isothiocyanate is an oil contained in plants like mustard and radishes (including horseradish). Plants use both of these chemicals as biological weapons against predatory animals. They irritate pretty much any soft tissue they come in contact with, which is what causes the wonderful burning sensation on your tongue. But they also cause the painful sting of post-chile-handling eye contact and a seriously runny nose. When your mucous membranes get hit by these chemicals, they become inflamed and go into defense mode. This means producing mucous to trap allergens and other undesirables, and keeping them out of your respiratory system by removing them via the nasal passage.
You might have noticed that if you’ve got a cold and are congested, the runny nose effect of spicy foods can make you feel a little better. Don’t be fooled by the healing properties of hot and sour soup and buffalo wings, though, because the relief is only temporary and really just makes things worse in the long run.
Capsaicin and allyl isothiocyanate’s irritation can cause the dilator naris muscle in your nose to temporarily allow more air to enter. Receptors in your nose then tell your brain that you’re breathing easier. It’s all an elaborate ruse, though, and when the effect of the heat wears off, you’re back to your old stuffy self, with plenty of extra snot brought on by your meal to boot!