In vivo localized water suppressed proton spectroscopy of human brain was carried out on 15 healthy volunteers and 2 patients suffering from a brain tumour and an infarction, respectively. The measurements were performed on a whole body MR system, operating at 1.5 tesla using the stimulated echo technique. Our preliminary results indicate that it is possible to detect a number of metabolites in the brain within a total measurement time of one hour. The dominant peaks in the spectra from healthy volunteers/are Nacetyl aspartate, choline and creatine/phosphocreatine. The spectra obtained from the brain tumour and the infarct, respectively, differed very much from those obtained in healthy brain tissue. Our preliminary results indicate that localized proton spectroscopy may contribute to non-invasive brain tumour classification and possibly also to the differentiation between tumours and infarcts in clinically doubtful cases.