From wikipedia (which may or may not have been submitted by a cr poster)
In the United States, overdose exposure to all formulations of “vitamins” (which includes multi-vitamin/mineral products) was reported by 62,562 individuals in 2004 with nearly 80% of these exposures in children under the age of 6, leading to 53 “major” life-threatening outcomes and 3 deaths (2 from vitamins D and E; 1 from polyvitaminic type formula, with iron and no fluoride).[3] This may be compared to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004).[4] In 2010, 71,000 exposures to various vitamins and multivitamin-mineral formulations were reported to poison control centers, which resulted in 15 major reactions but no deaths.[5]
Personally I believe that if you eat a varied diet and spend some time outdoors you shouldn’t take any vitamins (unless bloodwork shows that for some reason you’re still missing some)