This is a big lie about vitamin c and come up with this accusation often from people. I always respond with this, which was sent to me by a man that has been taking bowel tolerance doses of vitamin c for 20+ years, David Smith.
Vitamin c and kidney stones. As Dr. Thomas Levy, M.D. wrote, "What's this about vitamin C and kidney stones? Newsflash: A Harvard study involving over 50,000 people shows that, not only did vitamin C not cause kidney stones, but it reduced the incidence of kidney stones, and helped resolve pre-existing kidney stones....a study was conducted by Harvard Medical School, keeping it from being automatically undermined and discredited. A large population of women (85,557 to be exact) with no history of kidney stones was monitored for 14 years. The researchers concluded that "vitamin C intake was not associated with risk" of kidney stone formation....Previously, another large scale study found that: the intake of high-doses of vitamin C does not increase the risk of calcium oxalate kidney stones." In fact, the members of the group with the highest vitamin C intake "had a lower risk of kidney stones" than those with the lowest intake....high-dose vitamin C has been administered all over the globe for decades with no noticeable increase in the incidence of kidney stones."