Water is by far the most abundant molecule in tissues and the common solvent for all bioactive substances including drugs. Therefore, any changes in abundance, flow and quality of water will critically affect the biological actions of substances. Despite the importance, however, dynamics of water in tissues are poorly understood, in sharp contrast to those of solutes. This situation is mainly due to the lack of appropriate analytical tool to image and characterize water dynamics in living tissues with high spatiotemporal resolution. To overcome this technical limitation, we developed a multimodal multiphoton microscopy technique with stimulated Raman scattering (SRS) imaging ability. This SRS multimodal multiphoton microscopy allows us to visualize water dynamics in brain tissues. In addition, simultaneously obtained fluorescence images enables us to characterize water dynamics together with that of fluorescent dyes (solutes), in the context of cellular structures. In this talk, I will introduce the technical background of this technique and new information obtained from our research.