My dog Gwen, who is a pit-lab mix, keeps getting this black/brown stuff in her ear. It's always the same ear and no matter what I do it always comes back. I take her to the vet all the time and they always say the same thing, it's both bacteria and yeast. I get meds for both, follow the directions, don't miss any doses, and do my best to keep an eye on what she does. The ear will be fine for a few days, sometimes up to about 3 weeks, and then the substance comes back. I've tried cleaning the ear out daily, putting peroxide in it, using the meds the vet gives me, oral and liquid antibiotics, liquid cleaning solutions from the vet, and nothing works. I know that water in the ear can make this type of thing happen, but she doesn't go swimming, she has long ears so rain doesn't get in them, when I bathe her I put stuff in her ears to prevent water or soap from getting into them, I just don't know what's going on. Does anyone have any ideas about what I should be doing or what is going on in her ear?