The aim of the study was to determine if oral pentoxifylline prevented dialysis induced hypoxaemia and neutropaenia. Fifteen stable chronic haemodialysis patients were routinely dialysed using either a cuprophane or cellulose acetate membrane. Bloods for white blood count (WCC) and pO2 were taken at time 0, 20,80,140 and 200 min. The procedure was repeated in the same patients 2 h after the ingestion of 400 mg of pentoxifylline. There was a highly significant drop in WCC at time 20 min and pO2 over the dialysis period, which was not prevented by pentoxifylline. Pentoxifylline levels taken at time 0 in 11 patients were in the therapeutic range and it is concluded that pentoxifylline does not prevent dialysis induced neutropaenia or hypoxaemia.