Friends of mine on another board all use this solution- it works great!!!! It's kind of a double barrel approach, if the problem is fungal the Gentian Violet will take care of it, and if it's bacterial the Boric Acid will work. If the ear is raw from the dog scratching you can substitute Witch Hazel for the alcohol.
16 oz. bottle isopropyl alcohol (or witch hazel)
4 tablespoons Boric Acid Powder
16 drops Gentian Violet 1% Solution
I found extract of Gentian Root at the health food store- it's not even purple! If you do find the purple kind be forwarned that it stains.
You can fill the ear and massage in, I use those round quilted cotton makeup sponges (they don't fall apart like cotton balls). I soak one good, then stick it down in Earnest's ear, and let him shake it out. It stays in long enough to do the trick- I've never had to treat his ears for more than a few days, I usually do it morning and night every other day for three times.
If your dog gets frequent yeast infections you might try switching to a rice-based food, corn and wheat in the diet can make a dog more susceptible, since I switched a year ago Earnest hasn't had a problem with yeast except once, when I fed him a bunch of regular dog biscuits in a relatively short period of time.
