Scientists have been investigating the effects of fluid motion on the efficiency of different systems. In recent years, mechanical engineers have proven their ability to scientists of medical science. They have also introduced innovative methods for designing new medical devices and the improvement of the existing tools. These efforts have played an important role in recent advances in health care treatments. For instance, CFD simulations help scientists to investigate and understand the blood flow non-Newtonian behavior in artificial organs such as heart and kidney. Fluid and gas motions are present in every part of our body. We can model all of them by CFD tools. Using CFD simulations has significant effects. Such as reducing the cost and the required time for the optimization of medical devices and artificial organs. Generally, we can say that using computational fluid dynamics in the medical sciences is an efficient way to combine and use engineering sciences in the medical sciences.