In a double-blind study, 24 Down syndrome children, ages 6 to 17 years living at home, were given a megadose multi-vitamin/mineral supplement for 4 months. A matched group of 23 children received a placebo in identical form. The children's IQ, vision, and visual-motor integration were tested before and after supplementation, and weekly checks were made to monitor behavioral changes. No differences were found on any measures as a result of supplementation.