Twelve patients suffering from mental anorexia were examined on clinical and biological grounds, based on the hypothesis of the functional depression of the noradrenergic track. The initial values of MHPG and of catecholamines were below normal. The quantitative results for depression and retardation were lessened significantly under beta-stimulant treatment. Only glucuro-conjugate MHPG excretion increased significantly, but the MHPG values were much lower than normal at the end of the treatment. The correlations between biochemical and behavioural parameters were worth noticing as far as the retardation scale was concerned. The present study shows the advantage of the dexamethasone suppression test and of the response of TSH under TRH.