Too much of this vitamin can lead to kidney stones!

Dr. Reznicek, a urologist, describes which vitamin taken in high doses can lead to kidney stones. In some cases, massive doses have led to kidney failure and even death. This vitamin is often found in supplements for cold remedies and for "immune health." Some alternative medicine clinics offer IV vitamin therapy for treatment without appropriate evidence or clinical trials. Normal doses of the vitamin are healthy and are necessary for collagen synthesis among other physiological processes.

https://www.ncbi.nlm.nih.gov/pubmed/1...
https://www.ncbi.nlm.nih.gov/pubmed/1...
https://www.ncbi.nlm.nih.gov/pubmed/2...
https://www.ncbi.nlm.nih.gov/pubmed/2...
https://www.ncbi.nlm.nih.gov/pubmed/7...

https://pacificnorthwesturology.com

A good review article for reference: https://www.ncbi.nlm.nih.gov/pmc/arti...