The purpose of this study was to establish the effects of intravenous dimethyl sulfoxide (DMSO), a solvent used in a wide variety of products (medicines), on kidney function in the newborn rabbit. Three groups of anesthetized, ventilated, normoxemic 4- to 8-day-old New Zealand White rabbits received a 90-min intravenous infusion of DMSO at a dose of 1.11 (group 1), 16.5 (group 2) or 111 microgram/ kg/h (group 3). The only change observed in the animals of group 1 was a significant increase in filtration fraction (FF; p < 0. 001), whereas no change at all was observed in the renal functional parameters of the animals of group 2. The highest dose of DMSO (group 3), however, caused a very significant (p < 0.001) decrease in renal blood flow (RBF) and a rise in renal vascular resistance (RVR), FF and urine volume (UV). Glomerular filtration rate (GFR) and systemic parameters such as pH, mean arterial blood pressure and heart rate did not change. The rise in GFR, RVR, UV (group 3 vs. 2) and FF (groups 3 vs. 2 and 2 vs. 1) was dose-dependent. No significant dose-dependent decrease in RBF was found. To the best of our knowledge, there are no previous reports on the effect of DMSO on renal function in the solvent doses used in this study. We ascribe the reported effects to the 'immaturity' of the newborn rabbit kidney. Consequently, this agent should be used with great caution in developmental studies.