A friend of mine has a small terrier they took to the vet to have it castrated, but the surgery got massively infected. The poor dog would hardly walk and they got antibiotics for it without much result, it would still almost drag it's hind legs along. I gave her some 24% sodium chlorite and told her to put 10 to 15 drops into it's drinking water. By the next day the dog was bouncing around wanting to go for a walk. She carried on with the drops for a few days to make sure no infection remained.
I had told her that the Sodium Chlorite would be changed intoby the dog's stomach acid, and it really worked.