Kidney stones are hard mineral deposits that form in the kidneys and can cause painful symptoms when passing through the urinary tract. Symptoms include pain in the back, side, abdomen or groin, as well as nausea, vomiting, blood in the urine, and frequent urination. Kidney stones can be prevented naturally by staying hydrated, eating less animal protein and sodium, and avoiding high-dose vitamin C supplements. Traditional Chinese medicine views kidney stones as caused by damp heat and blockages in the lower body.