Question: what does it mean to be alergic to something ?

Andrew Quigley answered on 16 Nov 2015:

When you’re allergic to something, it means that your immune system has an over reaction to something that is harmless; it is this over reaction that makes you feel sick. Anything that causes this over reaction, we call allergens. Common examples of allergens include: pollen, animal hair, peanuts, insect stings/bites. If any of you suffer from hayfever, that’s caused by an allergic reaction to pollen.

Scientists aren’t sure exactly why some people have these over reactions while most people don’t. It’s likely some combination of genetics and the environment though.

I’d be interested to hear what the other scientists have to say, this isn’t really my area!