I occasionally take Ginseng in the morning. I find it doesn't make me as nervous as coffee, and unlike coffee, it lasts all day and doesn't make me tired later. I do feel an increased heart rate, sometimes, which I'd say is the only negative side effect I've experienced. I usually take some a few hours before a Kung Fu class. I feel it makes me more alert, but exercise wakes me up anyway. BTW, Ginseng + caffeine is not a good combo, it's too much and keeps me from sleeping at night.
I think it's pretty cool to use in conjunction with martial arts. At our kwoon, there's a box of extra-strength and students can buy a bottle for 50 cents - I don't ever do this, because I prefer to drink it slowly. Ginseng also helped me get through a 13-hour drive recently.

Anyone else use Ginseng here? How does it affect your Kung Fu?

-FJ