This study measured the plasma and liver concentrations of cytokines, the distribution of blood lymphocyte subpopulations (CD4 and CD8), plasma levels of nitrite (NO3 –) and nitrate (NO2 –), intercellular adhesion molecule 1 (ICAM-1), cytokine-induced neutrophil chemoattractant 1 (CINC-1), prostaglandin E2 (PGE2), and peritoneal lavage fluid (PLF) levels of monocyte chemotactic protein 1 (MCP-1) and CINC-1 in order to examine the anti-inflammatory activity of the cinnamon extract in lipopolysaccharide (LPS)-exposed rats. The plasma concentrations of interleukin (IL)-1β, IL-6, and tumor necrosis factor α (TNF-α) were lower in the cinnamon extract groups than in the control group at both 2 and 5 h after LPS injection. Furthermore, the liver concentrations of IL-1β, IL-6, and TNF-α were lower in the cinnamon extract groups than in the control group at 5 h after LPS injection. Plasma IL-10 concentrations were higher in the cinnamon extract groups than in the control group at both 2 and 5 h after LPS injection, and liver concentrations of IL-10 did not differ significantly among all treatment groups at 5 h after LPS injection. The distribution of CD4 tended to increase, and that of CD8 tended to decrease in the cinnamon extract groups. The CD4/CD8 ratio was increased in the cinnamon extract groups. The plasma concentrations of NO3 –/NO2 –, ICAM-1, CINC-1, and PGE2 and the PLF concentrations of MCP-1 and CINC-1 exhibited a tendency to decrease in the cinnamon extract groups. These results indicate that cinnamon extract can exert functional anti-inflammatory effects.