Horrible Science S01 E06 Gruesome Guts

Poo, pizza and disgusting germs! Why do we poo and how does digestion work? Who was Louis Pasteur and how did he help? Mark arrives at the studio with terrible stomach pains and asks The Shrinkings Scientists to find out what's wrong with him - in their toughest mission yet Dr Sensible, Professor Small and Junior get ready to fly up Mark's nose to investigate.