I give all my dogs brewers yeast tablets with garlic. All are in perfect health. great skin and coats. Their blood work is always good. My rescue sweetie had horrible skin and coat now she is pretty. I have never had a problem with it. Garlic is also in the BARF diet. A lot of people feed that diet and their dogs skin and coats look great and they are the picture of health. I do not feed onions. one I dont like onions. two they are toxic to dogs. Grapes are also bad for dogs. Causes kidney problems.