• Question: What causes that burning feeling when we eat a spicy food, a chili for example?

    Asked by tosty55 to Aggelos, Andrew, Eileen, Naomi, Shane on 15 Nov 2012.
    • Photo: Andrew Jackson

      Andrew Jackson answered on 15 Nov 2012:


      The chemical capsaicin is what makes chilli peppers hot on the tongue. It is an irritant, meaning that it makes your skin red and feel like its burning. Chilli plants use this to stop mammals eating their fruit – instead, birds dont get burned by capsaicin so they can happily eat the fruit and spread the seeds far away to grown new chilli plants.

      I love chillis, and can eat even the hottest ones on my food. Habanero Tabasco sauce is my favourite and goes on just about everything i eat./

    • Photo: Naomi Elster

      Naomi Elster answered on 16 Nov 2012:


      For chilli, it’s a chemical called capsaicin. Chilli probably evolved to contain this chemical (which in its pure form is used as a weapon!) in order to stop itself being eaten…

    • Photo: Eileen Diskin

      Eileen Diskin answered on 18 Nov 2012:


      The others are right about the bits in chili that make it spicy. But why does it feel so hot and spicy in our mouths?! Its because of our sensory neurons.

      Our neurons are cells that are good at transmitting information using signals (electrical or chemical) through our bodies. The sensory neurons are what transmit external inputs to our brain, so we know how to react. Our sensory neurons transmit information about light, sound, and touch using receptors – that are the bits the ‘grab’ the input.

      In the case of chili (and the chemical capsaicin), its ‘nociceptors’ that take the heat and pain associated with the capsaicin and pass along the message to our brain…so we respond by knowing that its hot!

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