Acute phosphate nephropathy or nephrocalcinosis is a tubulointerstitial nephropathy characterized by tubular calcium phosphate deposition - crystal nephropathy - and slowly progressive renal insufficiency during or following treatment with preparations containing sodium phosphate. We report a patient who developed nephrocalcinosis (crystal induced acute kidney injury) following the administration of a combination of oral and rectal sodium phosphate for treatment of postoperative constipation. A timely renal replacement therapy procedure may reverse the process of crystallization and the irreversible slope towards chronic dialysis.