I suffered from horrible sinus headaches over the past three months. After much researching, I finally found the culprit--ICE CREAM. I have craved Ice cream every day for the past 3 1/2 months. I always use Oragnic ACV so I knew that was not helping. I tried grapefruit seed extract in water and was very pleased with the results. No more sinus headaches since I've been on it. I used about 5 drops in an 8oz glass of water.