I will wholeheartedly echo Todd's recommendation to find a reputable product.

As well, and perhaps more importantly, you'll want to check the ingredients.
You'll find a lot of St. John's Wart products that include synthetic
ingredients--you don't want that.  I accidently purchased some capsules that
included synthetic materials and oh, did I regret it....definitely noticed a
"speedy" effect, became more sociable and aimlessly chatty, then suffered an
awful muscle tightening in my back later.

I also recall reading that you don't want to take too much.  I think 900 mgs
(per Todd's email) might be too much, but I'm not for certain.  Read up--I
imagine if you go to the health food store, you'll find a reference book that
can instruct you better than I.

Nita