The Witcher - Preview @ GameShark

The Witcher has been previewed at GameShark, with article particularly looking at character development and alchemy:

Along with physical hits, weapons inflict special damage via oils. Using the game's alchemy system, it's possible to create all manner of oils and potions to augment your arsenal and natural abilities. Dousing a blade in “Necrophage” oil, for example, enables you to poison enemies. Potions temporarily boost your powers, although at a risk of being poisoned. Unlike the carefree punch-drunk potion drinking binges of typical role-playing games, the concoctions drain your health if imbibed in excess.