I was told by a manager at my local health food store that vitamin C doses should be spread out--the body can only process so much. She said if I gave my kids too much, they would likely get diahrea. My kids were so sick last winter, and last week I ended up in the ER with my son, and it's only fall! I asked my pediatrician if there's anything I can do. He recommended that I give them a probiotic everyday, since most of your immune system is in your intestines. Also, he said to give the herb astragalus everyday as an immune enhancer. So I ordered both (kids versions) from iherb.com, and they weren't too expensive. In addition, the health food store manager recommended a multi-vitamin, and vitamin c. I do feel like I'm giving them a lot, but I don't care. If it will help, I will do anything. I am due with baby #3, and cannot endure another winter, healthwise, like last winter. Good luck to you.