Can you use Echinacea if you have MS?

No direct or indirect correlation between Echinacea use and MS has ever been identified. The National Multiple Sclerosis Society, however, does have a stated position on the use of Echinacea by people with MS:

"...echinacea may stimulate the immune system. This is a theoretical risk for people with MS because their immune systems are already inappropriately stimulated. No study has been done to investigate this theoretical risk in people with MS."

I would say that you would probably be OK using Echinacea to stimulate the immune system while you have a cold, but use beyond that period isn't a good idea. More study is needed before anyone can make a more educated recommendation.