The present work concerns the diffusion of nanoparticles in capillary-tissue exchange system. Nanoparticle are inoculated into the patient’s body by intertumoral administration. Thus, nanoparticles diffuse into tumoral tissues through diseased capillary walls. Blood in the capillaries is modelled as Jeffrey fluid. The resultant fluid is called Jeffrey nanofluid. In this model we have described diffusion occurring through the capillary walls into the surrounding tissue. The mathematical results are obtained analytically and have been compared with numerical solution. Graphs have been plotted using MATLAB. The effects of shape factor of nanoparticles, volume fraction of nanoparticles, Jeffrey fluid parameter, viscosity index and viscosity parameter has been observed on velocity and concentration of nanoparticles diffusing into the tissues. A noticeable observation states that brick shaped nanoparticles diffuse most rapidly i.e., have higher diffusion rates than other shapes