Isoorientin inhibited proinflammatory cytokines in the sera and cortices of endotoxemia mice. Isoorientin (25 and 50 mg/kg/d, ig) and LiCl (100 mg/kg/d, ig) were given once a day for 5 days, and after 30 min of the last administration, LPS (5 mg/kg, ip) was injected. The blood and tissues were collected after 6 h of LPS injection. IL-1β (a), IL-6 (b), and TNF-α (c) in the sera were detected by ELISA (n = 6, 6 biological replicates). IL-1β (d), IL-6 (e), and TNF-α (f) in the cortices were detected by qPCR (n = 3, 3 biological replicates). The data were expressed as mean ± SEM. Statistical analysis was done using ANOVA. ∗P < 0.05 versus the control group. #P < 0.05 versus the LPS group.