hi sunshine:activated charcoal is usually made from cococnut shells or can be made from hardwoods like oak or maple , the wood or cococnut shells are not burnt all the way ,so it can keep its highly absorbant properties , many people confuse it to with grilling or cooking type charcoal , that type of charcoal has many different impurities and is very bad for you ( its not the same stuff) activated charcoal can absorb around 6000 known toxins including mercury ,this is why it is used in emergency rooms for most accidendental poisoning cases ( good luck at the dentist)