London - Most spicy foods contain a chemical called capsaicin - this provides the “heat”.
However, this is an irritant, and the body immediately tries to “wash it out” by causing salivation, a runny nose and watery eyes, says Andrew McCombe, a consultant ear, nose and throat surgeon at Frimley Park Hospital, Surrey.
This is the same reason why you get a runny nose when you sneeze.
But, contrary to common belief, eating a curry will not help you get rid of a cold, says Mr McCombe.
This is because, as well as acting as a decongestant, spicy food triggers mucus production. So people who eat spicy food while congested may end up more so than when they started, even if they experience temporary relief while eating.
Food that is hot in temperature rather than spiciness can also give you a runny nose. This is because the heat of the food or drink travels up the passages that connect the nose and the throat. This melts the mucus in the nasal passages and causes a runny nose. - Daily Mail