The effect of carnitine supplementation in valproic acid (VPA) treated patients presenting with hyperammonemia was investigated in 69 children and young adults seen at the Zentrum der Kinderheilkunde, Goethe-Universitat Frankfurt, and Universitat Erlanger, FRG. Plasma total carnitine was low (27 mcmol/1 cf normal of 40 mcmol/1) in 48 tested. After supplements of carnitine (1 gm/m2 per day) in 15 patients, the plasma ammonia decreased by 25% after 9 days and 46% after 80 days. The plasma free carnitine was increased by 12%. Plasma ammonia concentrations were significantly correlated with free plasma carnitine %. 
COMMENT. Carnitine supplementation was recommended in VPA-treated patients with hyperammonemia. The risk of VPA-induced Reye’s-like syndrome could not be determined from this study.