I'm at work and can't take the time to tell you all the good that Echinacea has done for my husband and I but I wanted to post this link to a post Uny made, loads of GREAT information contained within! Be sure and read all the links too :-)
I don't know anything about isocort and can't do a search right now but you'll have the knowledge regarding all the flawed studies that are out there about Echinacea once you read the links in Uny's post.
My husband and I both take 4 droppersful at least 3 times a day for me (except for a hit and miss day or two sometimes) and twice for my husband everyday for well over a year and I know Uny takes it everyday too.