Previous reports of hypocalcemia and hyperphosphatemia following use of phosphate enemas have either been in patients with renal disease or followed prolonged abuse of these products. The two patients described here had marked elevation of serum phosphate and concomitant lowering of serum calcium secondary to absorption of phosphate from a single administered enema. Associated moderate dehydration resulted in poor renal excretion of the absorbed phosphate and prolongation of hypocalcemia. Hydration was effective in permitting clearance of phosphate and restoration of normocalcemia.