Oxalate is a natural end product of metabolism in the body and should be expelled through your urine. If your oxalate levels are too high, the excess oxalate can combine with calcium to form kidney stones. These stones are hard masses of chemicals that can get stuck in the urinary tract and commonly cause severe pain.f your oxalate levels are too high, the excess oxalate can combine with calcium to form kidney stones. These stones are hard masses of chemicals that can get stuck in the urinary tract and commonly cause severe pain.