Menthol is a substance that creates a cool, tingling sensation when it touches your skin or mouth. You've probably felt menthol's effect if you've ever used cough drops, certain toothpastes, or muscle rubs: that fresh, minty coolness that seems to spread across your tongue or skin.

Menthol comes naturally from peppermint and spearmint plants, though chemists can also make it in laboratories. When menthol touches the nerves in your skin or mouth, it tricks them into sending “cold” signals to your brain, even though nothing is actually getting colder. It's like your nerves are being gently fooled.

People use menthol in all sorts of products. Cough drops contain menthol because that cooling sensation can soothe a sore throat and make breathing feel easier. Muscle creams use it because the cool feeling can distract from aches and pains. Some lip balms include menthol to create a refreshing tingle.

When you see “menthol” on a product label, you can expect that characteristic minty coolness.