Rehmannia (Rehmannia glutinosa) is indigenous to China, Japan, and Korea. It is also known as Di Huang. The root tuber can be used medicinally. Rehmannia contains iridoids (catalpol including ajugol, aucubin, melittoside, rehmaniosides A to D), monoterpene (rehmapicroside), ionone glucosides (rehmaionones A and B), monosaccharides/oligosaccharides, and steriods (sterols, including beta-sitosterol, campesterol, stigmasterol). Rehmannia has antibacterial, immunosuppressive, and antihepatoxic effects. In traditional Chinese medicine it was used as a diuretic and for nourishing and strengthening the liver, kidney, and heart. It has been used for a variety of ailments.