I have been using colloidal silver now for years on my pets, my children, my grandchildren, my spouse, my friends and myself. It is the best natural antibiotic out there and can be used topically and internally.
I have older pets (17 and 18). My cat is very susceptible to UTI's and the silver is the only thing that seems to clear it up. The nice thing is that it doesn't wipe out the beneficial bacteria! There have been reports of silver "building up" in the system, however this has never been shown to be toxic. I even got my Naturopathic vet prescribing it to her "fur" clients. It has been used for hundreds if not thousands of years, however with the pharmaceutical companies shunning anything natural because of big $$$$$$ it was put on the back shelf.
For people with children, don't forget-----babies get drops of it put in their eyes at birth! I would also suggest 1/4 teaspoon 3 times a day. I fill a small syringe and administer directly into the mouth. 10ppm or 20ppm seems to work well.