Prompted by a series of hepatitis-like cases in patients on regular haemodialysis treatment, the sets of polyvinylchloride (PVC) test tubings used were submitted to perfusion experiments. The perfusates from four commercially available tubings were also investigated. Diethylphthalate (DEP) could be identified by by IR and PMR spectrometry in the perfusate from the test tubings. UV spectrometry proved the presence of other non-identified substances in the perfusate from both the test tubings and from some of the other tubings.