Multivitamin preparations are commonly administered to regular dialysis treatment (RDT) patients. Serum Vitamin A was measured in 72 patients on RDT. Elevated serum Vitamin A levels (102.29 +/- 26.95 microgram/dl [3.57 +/- 0.94 mumoles/l]) were found in the dialysis population (normal 40.98 +/- 6.71 microgram/dl [1.43 +/- 0.23 mumoles/l]; P less than 0.0005). Serum Vitamin A levels increased with duration (months) of dialysis but not with frequency of dialysis (twice or thrice weekly). Patients taking a VitaminA-containing multivitamin preparation had higher serum Vitamin A levels than those on a non-Vitamin A supplemented diet. Bilaterally nephrectomized patients had the highest serum Vitamin A levels while patients with obstructive uropathy had the lowest levels. Serum Vitamin A levels did not correlate with symptoms of uremia. Positive correlations were found with serum levels of calcium, cholesterol and triglycerides. Patients receiving a Vitamin A supplement had higher serum cholesterol levels than non-supplemented patients. Vitamin A might be a factor in the high incidence of cardiovascular disease in RDT patients. We therefore advise discontinuing the long-term administration of Vitamin A-containing multivitamin supplements to patients on RDT.