This review focuses on studying liquid flow through low-density fibrous porous media, particularly tissue grades of papers. It discusses experimental designs, factors affecting liquid flow, and various versions of the Lucas Washburn equation and permeability expressions used to estimate liquid flow in these media. While a comprehensive model for liquid flow in these materials is lacking due to their structural complexity, numerous experimental methods have been developed to determine absorption properties, particularly for wiping and cleaning liquids. The review covers these methods, many of which are proposed by standard organizations. It is a valuable reference for scientists interested in understanding the models and methods associated with these materials. Manufacturers can also use this review to select and implement appropriate methods for the evaluation of absorption performance and quality of tissue products.