To receive benefits from apple cider vinegar, it has to be organic unprocessed vinegar. The kind you buy in the salad dressing ailse is useless.
I use vinegar to keep my sinuses healthy in the winter time. I started getting plagued with sinus infections about 8 years ago, every winter. Antibiotics would clear it up then it would come back, maddening.
Then I came across a post in another forum about using raw vinegar. I knew it was good for arthritis, and had tried it for that many years ago. It HAD worked, but the taste was so bad I didn't keep it up. But I was desperate for something to control these winter sinus issues.
This is what I do: I mix up a solution of one part vinegar (1/2 cup) to four parts water (2 cups), two tablespoons of organic honey (best if produced locally, to help with local allergies) and a tablespoon of cinnamon. (cinnamon is antifungal) I really should be using more cinnamon, but I hate it to have had to work up to it. I started with only 1/4 teaspoon, so being up to a tablespoon is pretty good.
I drink 6 ounces of this mixture every day. I take a break from it every so often because vinegar is rough on the esophagus, but I can always tell when I've gone too long as my sinus symptoms come back.
Drinking it down gives instant sinus relief, but if you have a long term infection it takes a few weeks to clear it up completely.