Polyethylene glycol 4000 as a continuously administered non-absorbable faecal marker for metabolic balance studies in human subjects.

The use of polyethylene glycol 4000 as a non-absorbable, continuously fed faecal marker is described. The intestinal handling and transit of polyethylene glycol is compared with that of chromium sesquioxide and barium sulphate. Polyethylene glycol is an acceptable non-absorbable faecal marker for calcium, phosphorus, and fatty acids, and has several features which commend its use in preference to insoluble chromium sesquioxide and barium sulphate particularly when marking water-soluble dietary constituents.