It's the stuff that keeps their gut healthy with good flora/bacteria. If the dog has been given antibiotics or steroids....they usually suffer from an overgrowth of yeast....which results in stinky ears and gas.
I use Dinovite which is a supplement you can order on the net without a prescription. It's in powder form and I mix it with a small amount of wet canned food. You give it every day. I also add fish oil capsules on top.
I have two dogs (mutts) who had severe flea allergies and the waxy ears. Their fur fell out and they chewed themselves.....no matter what flea product I used. The vet wanted to start them on prednisone....but I've had such bad results from that in the past with other dogs... I decided to do a little research on more natural products. It took about 3 weeks of a daily regime before I began seeing real results. Their hair came back and they stopped the chewing......plus, the ear problems disappeared. It's worth a shot!