Erxian Tang, from the Clinical Manual of Chinese Medicine Formulas, is a formula developed by Professor Zhang Bo-ne of Shanghai University of Traditional Chinese Medicine in the 1950s for perimenopausal syndrome (menopausal syndrome), consisting of six herbs: Xianmao, Xianling spleen, Baji Tian, Angelica sinensis, Zhi Mu, and Huang Bai. It has the effect of tonifying the liver and kidney, nurturing yin and helping yang, and is mainly used for menopausal syndrome and elderly hypertension. The author applied this formula plus and minus in the clinical evidence to treat insomnia in elderly patients and achieved satisfactory results, which are summarized as follows: 1. If the yang is full, the yang is full, the yang stilts are not allowed to enter the yin, the yin is deficient, so the eyes do not close”, indicating that the yang does not cross the yin is the pathogenesis of sleeplessness. We found in the clinic that many elderly patients with insomnia, the pathogenesis of the heart and kidneys do not cross, as the “medical method of circular” [1] cloud: “due to internal injury, caused by Su Bing Yang failure, there is due to kidney Yang failure and can not start the real water to rise to cross the heart, the heart gas is not allowed to descend, so do not sleep; there is due to the heart blood failure, can not descend below the Jun fire to cross the kidney, the kidney water is not allowed to rise, also not sleep “The latter in this section belongs to the insomnia caused by the lack of intercourse between the heart and kidney due to hyperactivity of the heart yang and deficiency of the kidney yin, which is very common in clinical practice. The former in this section belongs to the insomnia caused by the non-interaction between the heart and kidney due to the deficiency of kidney yang, which is also more common in modern geriatric clinics, usually manifesting as insomnia, dreaminess, lack of energy, poor appetite, cold form and limbs, especially in the lower extremities, with a pale tongue, white slippery coating and sunken and late pulse. These patients often have the experience of craving cold and drinking cold in their youth, or working in air-conditioned rooms all year round. When they are young, their yang energy is strong and not enough to cause the disease; when they enter old age, their yang energy declines and they are unable to activate the real water in the kidney to help the heart, so the heart loses its nourishment and cannot descend to the kidney, resulting in sleepless nights. Shaoyin disease in the “Treatise on Typhoid” cloud “Shaoyin is a disease, the pulse is weak, but also want to sleep”, pointing out that Shaoyin disease is due to Shaoyin heart and kidney two injuries, Yin and Yang Qi and blood deficiency and lead to a class of diseases. Among them, “but want to sleep” is often manifested as lack of energy and drowsiness during the day, and difficulty in falling asleep and waking up easily at night. For this type of disease, we often apply Erxian Tang plus or minus treatment, with satisfactory results. 2, Erxian Tang formula Erxian Tang is composed of Xianmao, Epimedium, Baji Tian, Radix Angelicae Sinensis, Phellodendron, and Zhi Mu, which has the functions of warming kidney yang, tonifying kidney essence, intercourse with heart and kidney, and regulating flushing. In this formula, Xian Mao, Epimedium and Baji Tian are used to warm the kidney yang and energize the true water in the kidney to help the heart; Huang Bai and Zhi Mu are used to diuretic the fire and nourish the kidney to protect the yin, and help the heart fire to fall; Angelica nourishes the blood and invigorates the blood to regulate the rhythm of the flush and nourish the liver. The Book of Discernment discusses in detail the evidence of non-intercourse between the heart and kidney, and considers that the liver has the function of regulating the heart and kidney and making the heart and kidney intercourse. For example, it is said in the book that “if the heart wants to intermingle with the kidneys, the liver will pass its qi; if the kidneys want to intermingle with the heart, the liver will guide its fluid, so that the soul will be fixed and the mind will be at peace”. Therefore, if Bai Shao is added to soften the liver and nourish the liver, and Chai Hu is added to clear the liver and relieve depression, the effect will be better. In addition, for Yang deficiency, we can add Radix et Rhizoma Pseudostellariae, Radix Ginger and Radix Cinnamomi to strengthen the effect of warming the Kidney-Yang; if there is heat in the Heart meridian, we can add Bamboo Leaves and Lotus Heart to clear heat and remove annoyance.