Catnip is a mild sedative, in bigger doses it works for sleep. My herbal books claim it's milder than valerian, but personaly... I find it stronger.

ANd it tastes pretty well as a tea and has nice smell (so it makes it extra relaxing). In small dose (half teaspoon per cup or so), it's relaxing... nothing of the stoned effect. Higher doses for sleep seem to knock me out within an hour... or at least relax me enough that I am able to get some rest.

One possible side effect is it gives me vivid dreams... but nothing of nightmare sort. So, I don!t mind that much.