Stool surface tension

Stool surface tension refers to the physical interfacial tension at the oil-water boundary within fecal matter. In clinical pharmacology, this physical property is the primary target for emollient laxatives, commonly known as stool softeners, such as docusate salts (StatPearls, https://www.ncbi.nlm.nih.gov/books/NBK555944/). These drugs act as anionic surfactants or detergents that lower the surface tension, facilitating the emulsification of fecal material and allowing water and lipids to penetrate the stool mass (NIH/PubChem, https://pubchem.ncbi.nlm.nih.gov/compound/Docusate-sodium). This increase in hydration results in a softer stool consistency, which reduces the straining and effort required for defecation. While not a biological molecule like a receptor or enzyme, stool surface tension is a significant therapeutic target in the management of constipation, particularly in patients who must avoid the Valsalva maneuver, such as those recovering from myocardial infarction, abdominal surgery, or those suffering from painful anorectal conditions (Mayo Clinic, https://www.mayoclinic.org/drugs-supplements/laxative-oral-route/description/drg-20070683).

Other names

Fecal surface tensionInterfacial tension of stoolStool interfacial tension

Reduction of the surface tension at the oil-water interface of the stool, which allows for the enhanced penetration of water and fats into the fecal mass.