Megavitamin therapy involves the intake of very high doses of vitamins. A megadose is an intake of 20 to 600 times the recommended daily allowance.
History
Megadose vitamin therapy is believed to have started in the early 1950s when "a few psychiatrists began adding massive doses of nutrients to their treatment of severe mental problems. In 1968, the Nobel-prize-winning scientist Linus Pauling coined the term "orthomolecular" to describe the treatment of disease with large quantities of nutrients. In the early 1970s witnessed the popularization of vitamin 'megadoses', usually at intakes of 20 to 600 times the Recommended Daily Allowance,... because these substances can be obtained over the counter, the practice of megadosing is now extensive. Vitamins were discovered decades ago but only recently have they been used as advanced cancer treatments... Vitamins in megadoses that are self-prescribed or administered as potentially beneficial anticancer treatments, however, should not be considered harmless.