Glycosaminoglycan contents were evaluated in plasma and urine samples from volunteers treated intravenously with a mixture of dermatan sulphate and heparin, combining a novel liquid chromatographic-mass spectrometric technique for the determination of oligosaccharides from glycosaminoglycans with a classical technique for the extraction of glycosaminoglycans from biological samples (precipitation with cetylpyridinium chloride). In plasma samples dermatan sulphate and heparin can be measured for 2 h after treatment; urine excretion was detectable for 24 h. These results suggest that this novel approach is promising for future studies on the pharmacokinetics of glycosaminoglycans, although some technical aspects need further improvement, mainly regarding the procedures for sample clean-up; cetylpiridinium precipitation is a complex procedure and the recovery is limited.