5 cirrhotic patients with latent distal renal tubular acidosis (RTA) and 5 cirrhotic patients with normal distal acidification ability were studied. All the patients were maintained on a 80 mEq/day sodium diet for at least 5 days before the study. Only 2 of the 5 patients with RTA showed a reduced daily sodium excretion while the 3 other patients with RTA had a normal natriuresis. Acidification ability was retested in all the patients after increasing sodium distal delivery by intravenous administration of ethacrynic acid. Some hours after the maximal natriuretic effect induced by ethacrynic acid, a normalization of the acidification test was seen in all patients with RTA. These findings support the concept that although sodium metabolism alterations are not the only factor in the pathogenesis of RTA in liver cirrhosis, reduced availability of sodium at the distal tubule may impair tubular acidification, probably by influencing the distal transtubular potential difference.