Within the scope of this thesis pharmaceutical excipients like cellulose and starch were analyzed using Raman spectroscopy and environmental scanning electron microscopy (ESEM). Raman spectroscopy as well as ESEM allows studying the influence of water on the behavior of these substances. Raman spectroscopy was proved to be a suitable tool to characterize molecular properties also for polar substances. Both the differentiation of materials or conditions and the influence of water on powders, gels, or films were shown. ESEM was used for the characterization on the morphological level. Improved resolution and depth of focus are the main advantages over light microscopy. A sample preparation known from classic scanning electron microscopy is not needed and contemporary analysis of production processes, experiments with unaltered samples, and in situ-experiments were performed. Substances were classified due to molecular varieties via cluster analysis. Morphological differences after the extrusion of celluloses were observed using the ESEM technique. In this regard a changed binding of water depending on the water content was shown by Raman spectroscopy. Furthermore, the gelation of cellulose ethers was characterized by means of Raman spectroscopy. Starch gels show differences within the process of retrogradation and starch films have a different behavior during swelling.