In a group of liver cirrhosis (LC) patients subjected to a rectal ammonium overload test, the effect of L-carnitine on ammoniemia and on the type A numerical connection and star clock psychomotor tests has been evaluated. On comparing 40 LC patients given L-carnitine with 40 control cirrhotics given a placebo, no significant differences were observed in ammonium levels after performing the overload test in both groups. However, on studying the patients with the greatest liver involvement, those given L-carnitine showed smaller elevations in ammoniemia and better responses to the psychometric tests than those receiving the placebo. The results obtained emphasize the need to continue testing the effect of L-carnitine using either similar tests or carrying out long-term evaluations to determine its protective effect in the appearance of hepatic encephalopathy, perhaps even including its evaluation in the treatment of established encephalopathy.