We describe a technique for measuring the water content of stools by the Karl Fischer method. The analysis is based on removal of water into a mixture of methanol/chloroform (1/2), after dispersion of the stool by sonication in presence of solvent. An aliquot of the solution thus obtained is placed in themeasuring cell of a Karl Fischer apparatus and then analyzed in the classic way. We further describe the advantages of this method (odorless, precise, reproducible) in contrast to other current methods. In addition the same organic solution can also be used in determining the lipid content of stools.