I have been using Colloidal Silver. I get it at GNC and have not been sick since. As a matter of fact when ever I get that feeling in my sinuses that tells me I'm about to get sick I take just a small amount ( about a shot glass amount) and it almost instantly goes away. It feels like I'm drinking fresh air.

I just bought a bottle of multi colloidal minerals because it was big and inexpensive at GNC.