Proton ((1)H) magnetic resonance spectroscopy (MRS) is a noninvasive method that can monitor the metabolic changes in most brain diseases. This technique is now available on current 1.5 Tesla magnetic resonance units and does not require sophisticated software or time-consuming post-processing techniques. Previous studies using single-voxel techniques showed the usefulness of MRS for the diagnosis of brain tumor despite some technical issues, including spatial resolution and volume coverage. Recent advances have been made through the use of multivoxel techniques and metabolite maps, which allow assessment of both the entire volume of the lesion and the surrounding normal-appearing brain tissue. Recent studies suggest the potential of this technique to guide biopsies, to define radiotherapy targets, and to monitor patients after treatment. Some persistent drawbacks, including measurement time and spectral resolution, will probably be overcome in the near future.