Rhein is an active metabolite of diacerein and an anthraquinone found in Rheus (rhubarb). Rhein exhibits pro-inflammatory, anti-inflammatory, anti-diabetic, anticancer, antioxidative, anti-atherosclerotic, and anti-angiogenic activities. Rhein inhibits LPS-induced activation of NF-κB and production of IL-6 and IL-1β by inhibiting degradation of IκB kinase. Rhein also inhibits hyperglycemia-induced apoptosis in β cells in animal models of diabetes. In gastric cancer cells, rhein increases the Bax/Bcl-2 ratio and levels of cytochrome c, inducing mitochondria-mediated apoptosis and inhibiting cell proliferation. This compound also inhibits vessel plexus formation and endothelial cell migration. Additionally, rhein decrease H2O2-induced increases in malondialdehyde and lactate dehydrogenase levels and decreases in superoxide dismutase and glutathione activity, inhibiting apoptosis and oxidative injury.