Silver kills all bacteria sensitive to Silver, which can be good or bad bacteria, if I remember correctly.
Small amounts are not a problem because they are quickly taken up into the blood stream, bypassing most of the intestinal tract. Large amounts can kill beneficial stomach bacteria.
Agryria is the blue condition that you could theoretically get from taking Colloidal Silver. It would take massive amounts over a longtime to acquire blue skin, but it has been done on occasion.
I have used Colloidal Silver, but not a lot of it. I think I bought it when I had a sore throat. I don't even remember if it helped.
I use Miracle Mineral Supplement (Acidified Chlorine Dioxide) instead of Silver because it chemically reacts with acidic bacteria, killing it. Leaving the more Alkaline bacteria, which is generally the beneficial bacteria. Or so the Chemists claim.
Dan