How to prevent my dogs ear infection?

I took my dog to the vet a couple times and they gave me a medicine but it doesn't work. Her ears always red with black ear wax coming out of her ears. I told the vet and suggested changing her diet from Pedigree to Blue Buffalo and it's still happening. What kinds of food helps it and what medicines and things like that prevent it?

if the ear infections are due to yeast you could consider adding apple cider vinegar to the dogs diet ... the vinegar makes the body more acidic and yeast can not grow ... my dog used to get recurrent ear infections but since being on the apple cider vinegar she does not ... it must be raw, organic, unpasteurized apple cider vinegar (with mothers) for it to be of benefit ... i have a small 15 pound dog and she gets 1/4 teaspoon on both her breakfast and supper kibbles ... many websites suggest adding it to their water but my dog would not drink the water but she does not mind it on her food at all ... i am pretty sure blue buffalo is grain free but if it is not you might consider a grain free kibble ...

It sounds like you need a limited ingredient food formulated for dogs with food sensitivities. I'd suggest you try Nutro Natural Choice Grain Free Venison Meal and Potato formula. The venison is a novel protein that most dogs have not had before. It's a limited ingredient food especially formulated for the dog that has food sensitivities and allergies. It has a 100% money back guarantee so if your dog doesn't like it you can return it for your money back. It's an amazing food because it does not contain any of the usual foods that dogs are allergic to such as corn, wheat, soy, beef, artificial colors or preservatives. I'm a pet nutrition specialist with Nutro and have been feeding it for 25 years and it's worked great for all my pets. I started using Nutro back in the day when my lab mix had itchy, scratchy skin. Once she started eating Nutro her skin issues went away and I've been feeding it ever since. Here's a link to learn more about Natural Choice Grain Free and read some reviews. http://www.nutro.com/natural-dog-food/natural-choice-dog-food/grain-free-adult-venison-meal-potato.aspx Good luck and hope this helps