Depending on the breed of your dog, they may struggle with ear infections. To combat this, you can make your own natural disinfectant using a vinegar solution. Mix together one part vinegar and two parts water and drop a couple of drops into your dogs ears. The vinegar will help get rid of yeast and bacteria and to alleviate your dog's discomfort. However, it's not an alternative to a visit to the vet.
Because of its anti-bacterial properties, the vinegar will help get rid of any bad germs but again, if it's a more serious infection, you may want to consult your vet first to see if the solution is enough alone.