Understanding of the biofluid rheology attracts a vast majority of biophysicists. In order to understand collective motion of many particles, one should reveal details of the motion of a single cell. Giant unilamellar vesicles appear to be a well defined object for studying physical aspects of the dynamic of the biological cells. Investigated by the fluorescent light microscopy methods, vesicles reveal rather fruitful dynamics in external flows. For example, in a flow with non-zero vorticity component a vesicle finds its one of three different dynamical states – tank treading, tumbling or trembling. Time dependent elongational flow drives a vesicle from one dynamically stable shape to another through a dynamical wrinkling of the membrane. Tubular vesicles undergo a stretching transition to a dumbbell-shape in steady elongational flow.