I used Blockade by New Chapter last year when I was frequently flying cross country. I never caught anything, so I was pleased with it, even though it costs almost $1 per pill. The expiration date is 10/10, so I recently got out my bottle to see how many pills are left. There may have been 4 or 5, but they are all stuck together, to the bottom of the bottle, to the cotton.... If you try this product, be aware to store properly, or use it all in a few weeks.