Eriocitrin is a flavonoid isolated from lemon, which is a strong antioxidant agent. Eriocitrin could inhibit the proliferation of hepatocellular carcinoma cell lines by arresting cell cycle in S phase through up-regulation of p53, cyclin A, cyclin D3 and CDK6. Eriocitrin triggers apoptosis by activating mitochondria-involved intrinsic signaling pathway^[1].