After a year of constant yeast infections and allergies in my lab/aussie mix, someone told me to check the label on her dog food. Come to find out, Brewer's yeast was one of the number 1 ingredients. It seemed that the added yeast was making the problem worse. I switched dog foods to a product that did not list Brewer's yeast and have not had a yeast infection since. I don't know if this will work for everyone, but for anyone with animals prone to yeast infections, it's worth looking into.