Functional electrical stimulation (FES) modifies red blood cells (RBCs) flux in blood capillaries of muscle. In this work, we aim to investigate changes in the RBC flux in small and large capillaries due to FES using zinc oxide nanowires (ZnO NWs) based electrode at different stimulation parameters. The RBC flux was significantly increased immediately after stimulation, which was evident from decreasing light intensity measured in the region of interest. Clinical Relevance- FES has numerous forms and functions. The benefit of FES is the increased blood flow to a muscle which is contracted abnormally. This work explores the use of FES to increase the blood flow and RBC flux in blood capillaries of stimulated muscle as FES generate muscle contraction and absorption.