I'm a father of a 46year old male with CF. I heard about airborne last fall, before I had to fly to Texas to be with my son who was having problems. I bought it and used it for my flight down (from VA). I personnaly didn't have any problems. Help???? I mentioned it to my wife and my son and received the standard answer. He can not use, unless he talks to his doctor and gets an okay. This will never happen. I also used it on my flight home. I returned to TX in December for Xmas and used it again, on my way down and on my way back. Again, I had no problems. Did it help, I don't known. I didn't catch anything and did not get sick. I have heard one thing against it, recently. A single dose has 1000 mg of Vitamin C. 2000 mg is recommended max daily dose. Because of possible GI problems (he doesn't need any more of those) and other things, I just can't remember. So, from an old man in VA I would not hesitate to recommend 1 or 2 doses for those flying or in some other way, enclosed with people who might have an infections desease. I, personnallly think it has potential. Limit daily amounts. If you have CF and WILL talk to your Doctor, they will probably say it hasn't been tested adequately (probably right), probably will not help (maybe) and because it is not prescribe by a doctor, is a waste of time. Your call. This probably confused you more than helped you. I, myself, will continue to use it. Will my son, probably not. Bill