It depends on what you are going to do with it. Alcohol has an indefinant shelf life - where as a strickly glycerine base will eventually go bad. If you want to apply a tincture topically or you need it to get into the blood stream quickly, then you definately need an alcohol base. If you are giving it nutritionally/orally to a pregnant woman, an infant, or young child - then, I would use the glycerine base.