Taking too many of the wrong kind of supplements can contribute to the development of kidney stones but it turns out, drinking milk does not, according to the Kansas City infoZine. Which supplements are the “wrong” ones depend, of course, on what kind of stones you might develop but calcium oxalate stores are the most common. To avoid these, researchers say avoid too much salt and meat and high doses of Vitamin C. Some common high oxalate foods are coffee, green and black tea, cola, spinach, chocolate, strawberries, wheat bran and nuts. The newest research indicates that foods high in calcium actually help prevent stones.
There are many sources of vitamin C. I looked at the Q & A piece and didn't see any information on what type of C. There are some synthetic Cs that I would never take. I can't see a natural vitamin C being harmful.