I have used oregano oil orally many times for inner ear infections.
I just put a tsp of olive oil in a cup and a few drops of PURE oregano oil, mix with 1/2 cup of water and swallow. Has to be mixed well, because it can be VERY hot in your mouth. I have taken many more drops than this when I had internal infections of different kinds. It has always been successful in killing the infection. The negative to it is it can be hard on your stomach especially if you have a tender stomach and I do not know the long term results on ones kidney..
All I know is I have used all the natural methods of getting rid of internal infections, and the two best that I have ever found is Oregano oil, and I would put Grapefruit Seed Extract (GSE) as number two on my list. Often I will use 10-15 drops of GSE in water first every few hours to see if it will stop the infection first..if that does not work, then I go for the more potent oregano. I also have a trick where I put the drops of oregano on bread and then roll it up in pill like fashion and swallow.
BTW- many oregano products know that the public can be very stupid, so they have it already mixed with olive oil. I prefer to mix my own so I know how much I am actually getting. You can buy oregano already capsulized too.
I think this recipe is fairly well-known/common, but I thought I would share it here because I use it every time I get an ear infection (which is not that often), and it has cured me of all of them since I discovered it. One time several years ago I got a strange blister-like cyst in my ear canal, and this recipe cured that and brought almost immediate relief to the pain as well. The recipe is very simple: just combine equal parts of vinegar (I use regular white/yellow vinegar, but probably any kind would do), and Rubbing alcohol (70-90%), and put a drop in each ear and let it run down into the ear canal. When I had the strange cyst thing, I got a Q-tip soaked in the alcohol/vinegar mixture and then pressed it gently against the bump in my ear canal. Like I said, it felt better almost instantly, after having bothered me for weeks. That's when I first tried this recipe. Since then I have cured several other ear infections (including one my boyfriend had, who also said his ear felt better immediately). Both ingredients in the mix kill germs and the alcohol also has a drying effect, which I think is important if you have fluid build-up in the ear from the infection or swimming, etc.
I never tried garlic juice and it does sound like it would be painful but I've always used garlic successfully to cure an ear infection. Just score a garlic clove, wrap in gauze so there is no too direct contact and place in ear, preferably over night. Usually does the trick.
I've also used olive oil to soothe ear pain. Heat the oil a bit and dip cotton and make into a little ball to pout in the ear. The warmth and something in the oil immediately eases the ear pain and often is enough to cure the problem.