Grape Seed extract seems like a really wonderful supplement. When I'm looking at supplements to consider, I'll often just google "contraindications" for use of "whatever."
Here is an example for,Grape Seed Extract:
http://www.webmd.com/vitamins-supple...tract%20(grape
I have used Oil of Oregano tablets with great success for upper respitory problems and prevention of problems. I'm a big believer in the efficacy of these type of products.