Vitamin C megadosage systemic conditioning ("rebound scurvy"), preoxidant effects, iron overload, reduced absorption of vitamin B12 and copper, increased oxygen demand, and acid erosion of the teeth with chewing ascorbic-acid tablets. In addition, one case has been noted of a woman who had received a kidney transplant followed by high-dose vitamin C and died soon afterwards as a result of calcium oxalate deposits that destroyed her new kidney. Her doctors concluded that high-dose vitamin C therapy should be avoided in patients with renal failure. As discussed previously, vitamin C generally exhibits low toxicity. The (the dose that will kill 50% of a population)
Scurvy lambs, chickens, and ducks, along with lemons and oranges, due to which "some of our ill were cured of scurvy". Unfortunately, these travel accounts did not stop further maritime tragedies caused by scurvy, first because of the lack of communication between travelers and those responsible for their health, and because fruits and vegetables could not be kept for long on ships. In 1536, the French explorer Jacques Cartier, exploring the St. Lawrence River, used the local natives' knowledge to save his men who were dying of scurvy. He boiled the needles of the arbor vitae tree (Eastern White Cedar) to