OBJECTIVE We compared the ability of peritoneal dialysis, hemofiltration, and continuous hemodiafiltration to remove infused ammonium chloride. METHODS Anesthetized adult rabbits received an intravenous infusion of ammonium chloride. Two methods of removal of ammonium chloride were performed in each animal and compared. In group 1 (n = 6), peritoneal dialysis (dialysate = 75 ml.kg-1) and continuous arteriovenous hemofiltration (CAVH) with a polysulfone 800 cm2 hemofilter (Minifilter Plus; Amicon Division, W. R. Grace & Co., Danvers, Mass.) were simultaneously performed for 40 minutes. In group 2 (n = 6), peritoneal dialysis and continuous arteriovenous hemodiafiltration (CAVHD) (dialysate flow = 1000 ml.hr-1) were simultaneous performed for 40 minutes. In group 3 (n = 6), CAVH and CAVHD were performed successively in random order for 30 minutes each. RESULTS Animals had high and stable ammonium chloride and glutamine plasma levels during the experimental procedure. No significant difference in ammonium chloride clearance was observed between PD and CAVH (group 1). In comparison with PD or CAVH, CAVHD resulted in significantly higher clearances of ammonium chloride (40% +/- 10% vs 96% +/- 34%, respectively) and of glutamine (195% +/- 17% vs 77% +/- 25%, respectively). CONCLUSIONS The overall results indicate that CAVHD should be considered for hyperammonemia when peritoneal dialysis is indicated but unfeasible or inefficient.