In vivo MR spectroscopy (MRS) is currently one of the few methods allowing quantitation of biochemical markers (metabolites) in living organisms on human MR scanners. In terms of clinical applications, the relevance of MR spectroscopy is related to the fact that measurements are localized, non-invasive and are conducted without the use of ionizing radiation. Thus, the extracted metabolic markers can be evaluated by considering the tissue structure or functional parameters as they are assessed by MR imaging in order to gain insight into biochemical processes which accompany or even trigger morphological changes in diseases. Besides being able to conduct measurements in single voxels (eg in herds of disease, study volume ≥1 ml), MRS can be also combined with spatial encoding methods as they are known from MR imaging in order obtain 2- or 3-dimensional metabolite maps (Chemical Shift Imaging, CSI). Human applications typically comprise proton and phosphorus MRS scans (1H- and 31P-MRS), which are relying on the excitation of hydrogen and phosphorus nuclei of corresponding metabolites. Among other things, 1H-MRS can be used to access the density and integrity of different cell types (N-acetyl aspartate and myo-inositol in the brain) and cell membrane turnover markers (choline), which is particularly important for monitoring neurodegenerative and oncological diseases (see the upper chart in figure on the right). On the other hand, 31P-MRS offers the opportunity to quantify important energy metabolism markers such as ATP and phosphorus creatine as well as tissue pH value (see the lower chart in figure on the right). In general, the Medical Physics group is working on the development of new methods for acquisition, artifact suppression, processing and quantification of MR spectroscopic data from the brain and musculature.