Very rarely, large doses of some vitamins lead to vitamin poisoning (hypervitaminosis). Other causes include Menkes kinky hair syndrome and hypervitaminosis A. Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Hypervitaminosis D is a state of vitamin D toxicity. Hypervitaminosis A and hypervitaminosis D are the most common examples. At high levels, this form of the vitamin can be dangerous (Hypervitaminosis A). Hypervitaminosis A is usually treated by stopping intake of the offending food(s), supplement(s), or medication.