1H magnetic resonance spectroscopy (MRS) has attracted much attention in recent years. Since the proton is the most sensitive stable nucleus for MRS, and since almost all metabolites contain hydrogen atoms, it is possible to perform a noninvasive chemical analysis on tissues deep within the body of a subject. Technical solutions to the elimination of water and lipid signals as well as resolution of the large number of potential metabolite peaks have been found. Most current work is on the brain, much of it in humans. This review begins with a consideration of these technical problems and also localization, editing, quantitation, and interpretation of spectra. Two diseases are considered in detail: cerebral ischemia (including stroke and neonatal ischemic/hypoxic injury) and cancer; a further section briefly reviews studies on other diseases. In the immediate future, 1H MRS is likely to benefit from a number of technical advances: higher field magnets, better control of gradients and eddy currents, more sophisticated radiofrequency (RF) pulses, and 1H-observe/13C-edited spectroscopy all offer potential improvements. Another major improvement will come from increased user-friendliness of clinical spectrometers and use of automated objective methods for spectroscopic data analysis.