Several hydroxypropyl oligoglucoses were detected in the faeces of rats on diets containing hydroxypropyl starches with degrees of substitution varying from 0.025–0.106. The major components were tentatively identified as hydroxypropylmaltose, dihydroxypropylmaltotriose, and dihydroxypropylmaltotetraose. The digestibility of the hydroxypropyl starches was found to decrease with increasing degree of substitution.