Forty patients were studied at precisely timed 10 min intervals during transurethral prostatic resection under epidural analgesia. Blood gases, serum sodium, and volumetric irrigating-fluid balance were measured. A decrease in the serum sodium level of less than 5 mmol litre-1 was recorded in 28 patients (the 'normal TUR' group). In 12 patients, the decrease was 5 mmol litre-1 or more, which corresponded to an average absorption of irrigant of 1 litre of 2.2% glycine solution (range 0.6-2.9; the 'absorption' group). Mild metabolic acidosis often developed during the operations, but this was of similar degree in the two groups. It was concluded that uptake of irrigating fluid containing glycine does not alter the acid-base status so long as the TUR syndrome does not develop.