Fluid flow through modelled normal and stenosed capillary-tissue exchange system has highlighted issues that may have major applications for the study of diffusion phenomenon. The model incorporates modified Casson’s fluid representation for the blood flow through an axially symmetric stenosis. Assessment of the severity of the disease could be made possible through the variation of a parameter named as retention parameter. Symmetry of the distribution of the wall shearing stress and resistive impedance and their growth with the developing stenosis is another important feature of this analysis. The concentration profiles and associated physiological diffusion variables involved in the analysis for normal and diseased state have been determined.