Colloidal silver has shown itself to be useful for human health issues and apparently it can be useful for dogs also according to this article. Once you get to the page, you have to click on the "PDF" download button to read the full study.
My dog had an incomplete vaccination history (found this out after the fact). He contracted distemper. Outlook - certain death. He was, prior to the illness, fed a raw diet (we think this helped). Anyway, he stopped eating, drinking, etc. He would drink my expressed breast milk. It kept him alive. Also, we massaged him down twice a day with 10 drops tea tree and 10 drops lavender mixed in a 1/2 cup of a carrier oil. We also boiled water and put 5 drops of tt and lav. in it and had him inhale the steam once to twice a day. We thought he was a goner, but we kept at it. It's been almost a year since that and he is alive and strong!
(Ciudad Guzman, Jalisco, Mexico)