ELIXIR, in alchemy, the medium which would effect the transmutation of base metals into gold ; it probably had a wider meaning than "philosopher's stone." The same term, more fully elixir vitae, elixir of life, was given to the substance which would indefinitely prolong life ; it was considered to be closely related to, or even identical with, the substance for transmuting metals. In pharmacy the word was formerly given to a strong extract or tincture.