The doctors look at the awesome work that goes on inside the liver, and Dr Chris extracts snot from members of the public for a very useful experiment. Meanwhile, over in A&E, one patient has a massive lip from an allergic reaction and another has surgery to repair his broken nose.

The doctors use real stomach acid to do an experiment to reveal how the digestion process starts. Also, Dr Chris proves that the younger you are, the more sounds you can hear. Meanwhile, over in accident and emergency, one patient has broken his arm tripping on a kerb and another has banged his head on the handlebars of his bike.