Mercuritol is a make-believe or fictional substance that the lawyer in the legal TV drama "Eli Stone" says caused the title character's son to have autism. Mercuritol is supposed to be a mercury-based vaccine preservative and so some parents may confuse it with thimerosal, a real mercury-based preservative that has been used in vaccines.
Although there was no evidence that thimerosal was actually harmful or causes autism, it was removed from most childhood vaccines in 2001.
Sources:
CDC. Mercury and Vaccines (Thimerosal).
Institute of Medicine. Immunization Safety Review: Vaccines and Autism. 2004.
ABC Drama Takes on Science and Parents. New York Times. By EDWARD WYATT. January 23, 2008

