Optical manipulation of cells inside living animals can facilitate fundamental studies of structure and function of cells as well as the interactions between different cells, from which physiological insights into the cytopathogenesis and tumor cells migration could be gained. In 2013, we first achieved the goal of manipulating single red blood cells within capillaries in living mice by using infrared optical tweezers. Such an experimental achievement sheds new light on the study of optical manipulation in vivo. In this paper, we present a short review on the techniques involved in optical trapping in vivo, and further provide some examples of biomedical applications of this technology. Finally, we discuss the problems to be addressed for optical trapping through deep tissues as well as the potential solutions, from which more biomedical and clinical applications can be benefited.