Abstract We studied the variations in the concentration of metabolites with brain region and age in autistic individuals and normal controls using multiple analysis of covariance. We examined 55 autistic individuals (221 years old, 47 male and eight female) and 51 normal children (3 months15 years old, 26 boys and 25 girls). Single volumes of interest were placed in the frontal, parietal and temporal region on both sides, the brain stem and cingulate gyrus. The concentration of each metabolite was quantified by the water reference method. The concentration of N-acetylaspartate in the temporal regions (Brodmanns areas 41 and 42 ) in the autistic individuals were significantly lower than those in the controls (P 0.05), but concentrations in other regions were not significantly different between the autistic individuals and controls. This suggests low density or dysfunction of neurones in Brodmanns areas 41 and 42 in autistic individual, which might be related to the disturbances of the sensory speech centre (Wernickes area) in autism.