Hmmm... I started taking Colloidal Silver because, based on all the data I could find on it, the human immune system isn't complete without silver. Some people describe the use of Colloidal Silver as giving the human body a second immune system. To me, not having silver is like having only half an immune system. (Does that make me an optimist or a pessimist? *grin*)
I started using Colloidal Silver as part of my parasite program. I've used colloidal silver to knock out the beginnings of a strep throat (gargle with it, swallow, and then don't drink anything for several minutes, so the silver that's still there doesn't get washed away...). I successfully avoided getting ill when a sickness was sweeping through my workplace earlier. I've also used it to treat my children's stuffy noses.
Basically, I take one fluid ounce at night before bed, as a preventative measure. (My wife and kids also take it.) Since I make it myself, I don't have complete info on exact concentrations, but I think it's about fifteen parts per million (based on the color of the water -- a dark, golden color).