Figure 1. The paper towel method. The paper towel method was performed as follows (A). 1) Place paper towels on the experiment table. 2) Put the steel wire net floor (the bottom part of the mouse-dwelling portion of the metabolic cage) upside down on the paper towels. 3) Place the upper plastic cage (the upper plastic part of the mouse-dwelling portion of the metabolic cage) on the steel wire net floor. 4) Place mice in the cage and evaluate defecated stools seated on the paper towel by being dropped down through the steel wire net for required periods. Note water marks or diarrhea marks (thick arrows) generated on the paper towel by wet stools collected from mice of the 5-FU-induced diarrhea model on day 11 (B).