Years ago, we used to use a tablespoon of vinegar in a quart of water for douching after having our babies.
My sister was using 1/2 cup in a quart for two or three days and she said she was burning. I told her that was way to much, so she cut it down and was much better.
It also cleans up pet stains on terrazzo floors, cleans windows.
As for drinking, I've heard of 1 teaspoon in a glass of water first thing in the morning for cleaning out the bacteria, but to my way of thinking, if you can kill the bad bacteria, you will also kill the good bacteria at the same time.
I remember Dr. Oz saying to test the acid in your stomach to see if you have to much or to little.