Melamine is a widely-used chemical in industries In recent years melamine has been found to be involved in outbreaks of renal injury in Infants and animals Pathological studies indicated that the melamine-induced acute renal failure was related to the concurrence of melamine and other triazine analogs such as cyanunc acid In the present study human erythrocytes were used as an in vitro model to explore the cytotoxicity of melamine and its complex with cyanunc acid The results demonstrated that mixing melamine and cyanunc acid resulted in the formation of insoluble particles and that the insoluble melamine-cyanurate complex induced membrane damages of human erythrocytes The membrane damages included hemolysis K+ leakage alterations in cell shape and membrane fragility and inhibition of enzymatic activity By contrast either melamine or cyanunc acid alone had no effect on erythrocyte membranes The results of this study may provide a fresh insight into the melamine toxicology (C) 2010 Elsevier Inc All rights reserved