Science says chilli burns your mouth without actually burning it, here’s what capsaicin does to your nerves

The sensation after biting into a hot chilli can be intense: your mouth may feel as though it is on fire. Your lips can tingle, your tongue may burn, and your body may respond with sweating, watery eyes and increased saliva. However, unless the chilli is physically hot enough to cause a thermal injury, it is not actually burning the tissues in your mouth.