This week I had intense sinus pressure/headache from tree pollen. I tried drinking apple cider vinegar, but it made my headache worse almost immediately. I then read posts on EC in the sinus infection section about putting a teaspoon of ACV in a neti pot filled with warm, distilled water and rinsing the sinuses. I did this and felt so much better 10 minutes later! I hope everyone tries this. I have used a small amount of hydrogen peroxide in a neti pot before and gotten good results, but I think I prefer the ACV. It was milder and had an immediate effect!