KnowHow team explains: Spicy food that makes the nose run contains capsaicin, an extremely irritating chemical found in peppers. It is a vanilloid, a class of compound that includes vanillin, found in vanilla; eugenol found in cloves and cinnamon and zingerone found in ginger.

Capsaicin is believed to excite certain nerve fibres of the central nervous system that control the thickness and quantity of the mucus and other fluids secreted by the nasal passages and the stomach. Some herbalists recommend capsaicin-rich food as a natural decongestant.

Capsaicin is potent even in extremely small concentrations and is used in topical anaesthetics. In a minor Swiss study, researchers used it to replace decongestants in treating non-allergic rhinitis, in which the nose runs even when no allergens are present in the vicinity.

The study found that repeated spray application of capsaicin in the nasal passage (which had to be done by using local anaesthesia) provided some symptomatic relief. The initial application did produce some irritation.

Someone who accidentally ingests too much hot pepper should not drink water because capsaicin is insoluble in water and will do nothing to bring relief. Instead, one should consume yogurt or milk. This is because their oil content dilutes the action.

The question was sent by Nisha Dey from Calcutta