Today, pharmaceutical companies focus on developing more predictive models to describe the physiological processes more precisely so that experiments can be reduced, refined and replaced by the models. Physiological-based models can contribute to a better understanding of mechanisms attributed to pharmacokinetics (PK) and pathophysiological events. Hepatic drug elimination is a major PK process contributing to the loss of drugs in the body. Since the liver is a highly perfused organ with a porous structure, the principles of transport phenomena in porous media can be applied to the liver for modeling of hepatic drug elimination. This book, therefore, overviews concepts of porous media and local volume averaging method followed by elaborating the details of the porous media approach and its validity for modeling the hepatic drug elimination. The modeling approach and the analyses of hepatic drug elimination presented in this book should help shed some light on physiological based modeling, and should be especially useful to students, professionals and scientists who may be considering utilizing mechanistic modeling for analyzing PK processes or pathophysiological events in the body.