Precision-cut tissue slices (PTCS) are three-dimensional (3D) tissue explants that can be cultured ex vivo for additional studies of physiology, toxicology, and enzyme functions. Precision-cut tissue slices are typically made from human or animal organs, like lung, liver, kidney, etc. Tissue slices were first made by hand cutting with razor blades, but microtomes now help section PTCS that are consistent in thicknesses and have increased viability. Precision-cut tissue slices retain the anatomical architecture of the organ, cells in their original tissue-matrix configuration, metabolic activity, tissue homeostasis, and more. Thus, PTCS are a popular model for toxicological and pharmaceutical research because they closely recapitulate in vivo conditions. One area where PTCS is particularly useful is in respiratory research, where precision-cut lung slices (PCLS) allow for studying host-pathogen interactions.