WHY DOES PEPPER MAKES US SNEEZE ?

Our noses are designed to repel anything that enters through it except air. This is a kind of defence mechanism. The three main defences are the fine nasal hairs in the nostrils, mucus and sneezes – reflex actions caused when nerve endings in the mucus membranes are irritated.

A sneeze is a reflex that is triggered when nerve endings inside the mucous membrane of the nose are stimulated. Any rush of particles (eg dust) may trigger sneezes, but pepper is particularly irritating due to the substance that gives pepper its flavour.Pepper be it white, black, or green, contains an alkaloid of pyridine called piperine. Piperine acts as an irritant if it gets into the nose. It irritates the nerve endings inside the mucous membrane. This stimulation will cause you to sneeze. Actually, the nose wants to kick out this irritant and the only way it knows how to do this is by sneezing."
There are two main reasons why pepper is particularly sneeze-inducing.

• One reason is that it is often used when finely ground, and like any dust particle in the air, it can stimulate nerve cells inside the nose and trigger the sneeze reflex to forcefully clear out the offensive particulate.
• The second reason is the chemical composition of pepper. Pepper, regardless of the variety, contains a chemical called Piperine, which gives the plant its distinctive spicy flavour .

 Piperine is an alkaloid that stimulates the nasal nerve endings, causing the brain to trigger muscles in the nose and throat to expel the foreign particles in a sudden burst of air.