In this study, we investigated the effects of a glycine-containing diet (5%) on mortality and liver injury due to intravenous injection of endotoxin [Escherichia coli lipopolysaccharide (LPS)] in Sprague-Dawley rats in vivo. Fifty percent of the rats fed control diet died within 24 h after an intravenous injection of LPS (10 mg/kg), whereas feeding the rats glycine totally prevented mortality and markedly reduced an LPS-induced elevation of serum transaminase levels, hepatic necrosis, and lung injury. The elevation in serum tumor necrosis factor-alpha (TNF-alpha) due to LPS was also blunted and delayed significantly by glycine feeding. In a two-hit model (hepatic ischemia-reperfusion and injection of sublethal LPS), all rats fed control diet died, whereas 83% of glycine-fed animals survived with a significant reduction in transaminases and improved liver and lung histology. LPS elevated intracellular Ca2+ concentration ([Ca2+]i) in cultured Kupffer cells, an effect blocked almost completely by glycine. Glycine most likely reduces injury and mortality by preventing the LPS-induced elevation of [Ca2+]i in Kupffer cells, thereby minimizing toxic eicosanoid and cytokine production.