Diosmin is a type of plant chemical found mainly in citrus fruits. It is an oral phlebotropic drug used in the treatment of venous disease, i.e., chronic venous insufficiency (CVI) and hemorrhoidal disease (HD), in acute or chronic hemorrhoids, in place of rubber-band ligation, in combination with fiber supplement, or as an adjuvant therapy to hemorrhoidectomy, in order to reduce secondary bleeding. To control internal symptoms of hemorrhoids (piles), it is used with hesperidin.t can be found in Teucrium gnaphalodes, a plant endemic to the Iberian Peninsula.

Diosmin is used for treating various disorders of blood vessels including hemorrhoids, varicose veins, poor circulation in the legs (venous stasis), and bleeding (hemorrhage) in the eye or gums. It is also used to treat swelling of the arms (lymphedema) following breast cancer surgery, and to protect against liver toxicity. It is often taken in combination with hesperidin, another plant chemical.