The major players in my regimen are the zinc, echinacea, goldenseal, and some members of the B-complex, all of which are supposedly good for the immune system. The rest are just there as a sort of nutritional top-up, since sometimes you just don't get to eat as well as you might want to during a con, especially if your mealtimes and choice of dining establishments is subject to the unpredictable whims of a group outing. :)