To investigate the effect of cinobufagin on nuclear factor-kappaB (NF-kappaB) pathway of liver cancer cell line HepG2.Dual-luciferase cis-reporting system was used to detect the relative value of pNF-kappaB-TA-luc upon tumor necrosis factor-alpha (TNF-alpha) stimulation of NF-kappaB pathway. Western blotting was used to detect the protein level of NF-kappaB p65, and RT-PCR was used to detect the gene transcription level of intercellular adhesion molecule-1 (ICAM-1), a target downstream gene of NF-kappaB.At the concentration of 0.25 and 0.5 microg/ml, cinobufagin significantly lowered the relative value of luciferase (P<0.05). The results of Western blotting showed that cinobufagin significantly suppressed the protein expression of NF-kappaB p65. The transcription level of ICAM-1 was reduced by different doses of cinobufagin.The anti-cancer effect of cinobufagin may be related to its activity in inhibiting the activation of NF-kappaB pathway.