Lumbar CSF concentrations of homovanillic acid (HVA) and 5-hy-droxyindole-acetic acid (5HIAA) have been determined in ten patients suffering from chronic brain post-traumatic syndromes, at various length of time after the brain trauma. Lower concentrations of HVA (mean 21±14 µg/ml) compared to controls (mean 46±10 ,µg/ml) was observed in 7 cases; 5HIAA levels were within normal values. The 5HIAA/HVA ratio (1.59±0.66) was significantly higher (p<0.001) than the one recorded in controls (0.66±0.10). Monitoring of lumbar HVA and 5HIAA over time, before, during and after L-dopa treatment, revealed interesting correlations between modification of clinical picture and the levels of monoamines acid metabolites. The data indicate a profound alteration of brain monoamines in chronic syndromes following a severe head injury and suggest that measurements of lumbar HVA and 5HIAA in these patients may be of euristic and diagnostic