Well this was one of the things I was trying to work out. Taking into account what I have read, this is what I think the gel is supposed to do: The "micro-gel" is sprayed at the back of your throat. The back of the throat is where the cold virus actually infects the host (http://en.wikipedia.org/wiki/Common_cold#Pathophysiology). The gel traps any unattached viruses and washes them into the stomach alongside mucus (i.e. snot) where they are destroyed. Therefore, the gel supports the immune system by minimizing the virus population and so makes it easier for the white blood cells to wipe out the infection. Bear in mind this is a theory based entirely on A-level biology. I think it makes sense. Any pathologists on the forum? EDIT: Never mind, Norman beat me to it.