Rats were fed a diet containing 5% gum karaya for 24 h and faeces and urine were collected over 72 h. Faeces were examined, after methanolysis, by gas chromatography--mass spectometry and the quantity and monosaccharide composition of the faecal polysaccharide were compared with the dose and original composition of the gum polysaccharide. Gum-derived rhamnose was not found in the urine. Indications of minor quantitative changes in composition but no evidence of extensive degradation or absorption of gum polysaccharide, were found.