The human forearm technique was employed to determine changes in plasma levels and peripheral fluxes of TG, FFA and glycerol in a group of insulin independent diabetics before and after administration of sodium pentosan polysulphate. The forearm technique is based on simultaneous sampling of arterial and venous blood, and forearm flow measurement. Sodium pentosan is a heparinoid, hypolipidemic agent. Before drug administration it was observed that there was net TG uptake, and net glycerol and FFA release across the forearm. Following its injection, triglyceride uptake in the forearm progressively decreased. Sixty minutes after drug administration there was a release of TG into the circulation. Similarly, following sodium pentosan, glycerol release also decreased and culminated in eventual net glycerol uptake from the circulation. The release of TG showed significant correlations with the uptake of glycerol. As the phenomenon of net TG release was noted in more than one third of all significant exchanges across the forearm, these findings raise the possibility that TG release might, in part, contribute to the pathogenesis of diabetic hyper-triglyceridemia.