We have recently demonstrated that commercial PD-fluids inhibit the growth of a cultured mouse fibroblast cell line. Toxic substances produced during heat sterilization were believed to be the probable cause of the growth inhibition. The aim of the present study was to investigate if heat sterilized PD-fluids affect other cell types and other cellular functions than the growth of fibroblasts. The effect of three commercially and one laboratory made PD-fluid on cell growth of a mouse macrophage cell line (RAW) and a human neuroblastoma cell line (SH-SY5Y) was examined. The influence on stimulated release of tumour necrosis factor alpha (TNF alpha) from the macrophage cell line and stimulated superoxide generation from freshly prepared human leukocytes were also investigated. Compared to the filter sterilized PD-fluid, we found that heat treated PD-fluids significantly inhibited the growth of the two cell lines and impaired the stimulated release of TNF alpha and superoxide radicals. These results demonstrate that heat sterilization of PD-fluids produces substances that are cytotoxic regardless of the cell species, the cell type or the cell function tested.