|Classification and external resources|
Hypervitaminosis refers to a condition of high storage levels of vitamins, which can lead to toxic symptoms. The medical names of the different conditions are derived from the vitamin involved: an excess of vitamin A, for example, is called hypervitaminosis A.
Generally, toxic levels of vitamins are achieved through high supplement intake and not from dietary sources. Toxicities of fat-soluble vitamins can also be caused by a large intake of highly fortified foods, but foods rarely deliver dangerous levels of fat-soluble vitamins.
High dosage vitamin A; high dosage, slow release vitamin B3; and very high dosage vitamin B6 alone (i.e. without vitamin B complex) are sometimes associated with vitamin side effects that usually rapidly cease with supplement reduction or cessation.
Fat soluble 
With few exceptions, like some vitamins from B complex, hypervitaminosis usually occurs more with fat-soluble vitamins, which are stored in the liver and fatty tissues of the body. These vitamins build up and remain for a longer time in the body than water soluble vitamins.
High doses of mineral supplements can also lead to side effects and toxicity. Mineral-supplement poisoning does occur occasionally, most often due to excessive intake of iron-containing supplements.
Comparative safety statistics 
In the United States, overdose exposure to all formulations of "vitamins" was reported by 62,562 individuals in 2004 (nearly 80%(~78%, n=48,989) of these exposures were 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). 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). 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.
Before 1998, several deaths per year were associated with pharmaceutical iron-containing supplements, especially brightly colored, sugar-coated, high-potency iron supplements, and most deaths were children. Unit packaging restrictions on supplements with more than 30 mg of iron have since reduced deaths to 0 or 1 per year. These statistics compare with 59 confirmed deaths due to aspirin poisoning in 2003  and 147 deaths known to be associated with acetaminophen-containing products in 2003.
See also 
- Sizer, Frances Sienkiewicz; Ellie Whitney (2008). Nutrition: Concepts and Controversies (11 ed.). United States of America: Thomson Wadsworth. pp. 221, 235. ISBN 0-495-39065-8.
- Toxic Exposure Surveillance System (2004). "Annual Report" (pdf). American Association of Poison Control Centers.
- "National Center for Health Statistics".
- Bronstein, A. C.; Spyker, D. A.; Cantilena, L. R.; Green, J. L.; Rumack, B. H.; Dart, R. C. (2011). "2010 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 28th Annual Report". Clinical Toxicology 49 (10): 910–941. doi:10.3109/15563650.2011.635149. PMID 22165864.
- Tenenbein M (2005). "Unit-dose packaging of iron supplements and reduction of iron poisoning in young children". Arch Pediatr Adolesc Med 159 (6): 557–60. doi:10.1001/archpedi.159.6.557. PMID 15939855.
- Watson WA, Litovitz TL, Klein-Schwartz W, et al. (2004). "2003 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System". Am J Emerg Med 22 (5): 335–404. doi:10.1016/j.ajem.2004.06.001. PMID 15490384.