Ria (Washington, Dc) on 06/19/2016:

The rescue had a terrible cough when he came to me and promptly spread it to the other dog. I used colloidal silver ( a couple of capfuls) in each of their full water bowls along with about a teaspoon of 3% hydrogen peroxide. It cleared up within a month as I recall. I've had him a couple of years now and no recurrence. The foster has been returned to his owner and she has not had any further problems either.