Phosphate nephropathy consists of damage to the kidneys caused by the formation of phosphate crystals within the renal tubules, damaging the nephron, and can cause acute renal insufficiency or acute renal failure.

It frequently occurs following the ingestion of oral sodium phosphate solution (Visicol) for bowel cleansing prior to a colonoscopy. The risk of this complication is increased with age, underhydration, or in the presence of hypertension or if the patient is taking an ACE inhibitor or angiotensin receptor blocker. Other agents used for bowel preparation (e.g. magnesium citrate or PEG-3350 & electrolyte-based purgatives such as Colyte or Golytely) do not carry this risk.

When a kidney damaged by phosphate nephropathy is biopsied, the pathological findings are typical of nephrocalcinosis: diffuse tubular injury with calcium phosphate crystal deposition.