What Is an Allergy?

The doctors investigate how skin protects the body from extreme temperatures by dipping their hands in a liquid so dangerous it can freeze on contact. Dr Chris visits an allergy clinic to find out all about allergic reactions and meets two patients who have their suspected allergies put to the test. And the emergency ambulance team comes to the aid of a lady with severe tummy pains. Meanwhile, over in accident and emergency, things get fruity as one patient is admitted with a broken 'banana' arm and another needs treatment for a burn after dropping fried onions on her foot.