The hypothesis that both activated Kupffer cells and the spleen may be responsible for endotoxin-induced liver injury following partial hepatectomy was investigated. Male rats were divided into a sham group receiving laparotomy alone and three groups receiving a two-thirds hepatectomy; one group was given normal saline (NS) solution as a vehicle control, one group received intravenous gadolinium chloride (GC group) (7 mg/kg body weight) for 2 days before intravenous injection of endotoxin to inhibit Kupffer cell phagocytosis, and the third group simultaneously underwent splenectomy and partial hepatectomy (SH group). As endotoxin, lipopolysaccharide (LPS) (1 mg/kg body weight) was administered intravenously 2 days after surgery. In the GC and SH groups, phagocytic activity was reduced to approximately 40% of that in the sham group. The highest plasma tumor necrosis factor alpha (TNF-alpha) level (8,544 ± 1,223 pg/mL) was observed in the NS group at 1 hour after LPS administration, and the level was significantly reduced by GdCl3 or splenectomy (P < 0.05). Inhibition of Kupffer cell function and splenectomy attenuated functional and structural liver damage associated with the decreased hepatic infiltration of polymorphonuclear leukocytes (PMNs) and reduced priming of circulating PMNs in the early stage of endotoxemia following partial hepatectomy. Consequently, the 24-hour survival rate of the SH and GC groups was significantly improved to 50% and 80%, respectively (P < .05), while that of the NS group was 12.5%. These findings indicate that the modification of inflammatory mediator generation by splenectomy or inhibition of Kupffer cell function may be beneficial for the prevention of endotoxin-induced liver injury after partial hepatectomy.