In order to obtain, something of equal value is required. That is alchemy's law of Equivalent Exchange.
~ Alphonse Elric

Alchemists preform and/or study alchemy, an ancient form of research that predates science. Alchemy has two basic forms, the first is herbal alchemy, which consists of mixing potions and poisons from everyday vegetation or carefully grown ingredients; the second form is mineral transmutation, where one mineral is converted to a completely different one by the alchemist.