One commonly used herb for symptoms and patterns related to high blood pressure is Tian Ma or gastrodia rhizome. Research in China has shown it to be useful in the treatment of symptoms related to high blood pressure such as dizziness, numbness of extremities, tinnitus, headaches, and pain behind the eyes. It may have a sedative and tranquillizing effect. It has been shown to have usefulness for renal hypertension and essential hypertension. Another useful herb is Ye Ju Hua or chrysanthemum flower, which has been shown to have a prolonged effect of lowering blood pressure through peripheral vessel dilation. It has also been shown to increase blood flow to the heart. Another herb that is used to clear Liver Heat and is commonly used to treat eye problems that may be beneficial for high blood pressure is Xia Ku Cao or prunella. Chinese research has shown that it has a moderate vasodilating effect. These herbs are often used in combination by practitioners of Oriental Medicine in the treatment of patterns related to high blood pressure.