There are basically two types of vitamins: Fat soluble and water soluble. Fat soluble means that the vitamins the body does not use, are stored in the liver. Water soluble means that the vitamins the body does not use, are excreted in the urine. Taking significantly more than the 100% Recommended Daily Amount of a fat soluble vitamin can hurt the liver and the rest of the person. Fat soluble vitamins includes (but is not limited to) A, E, and Iron. With water soluble vitamins, there is more leeway in taking over 100%, but, even water soluble vitamins (such as the B vitamins) can hurt a person if they consume far greater than the 100% RDA. Also, in August 2010; “Consumer Reports” magazine had an article on supplements people should Never take because they can damage the liver. I suggest going to the library or Google.com and reading up on the supplements (legally sold in health food stores) that can cause liver damage if consumed.