Herbs for Mental Alertness

Which herbs would be good in an infusion for mental clarity? I forget and lose things all the time and when I try to communicate. If I'm very busy or tired at all I can't express myself or remember things to even conduct an intelligent conversation.

Rosemary, gotu kola and ginkgo is a nice tasting blend that I recommend for patients wanting to increase cerebral blood flow to improve the memory and mental clarity. If you find that you are getting a headache with this blend then reduce the amount of ginkgo being used. A cup of coffee has also been used for this purpose. The key with the coffee is to stop at one cup vs one pot.
Foods that tend to slow down mental function are sugar, wheat products and other mucous forming foods such a dairy. Exercise can also be of benefit.