Many people suffer chronically from insomnia and excessive dreaming, blurry vision and tinnitus, early greying and thinning of hair, along with persistent low back soreness, fatigue, and a stooped posture. Overall, they appear haggard and prematurely aged. From the perspective of Traditional Chinese Medicine (TCM), these issues are often rooted in Kidney Yin deficiency. Kidney Yin is central to nourishing the viscera, sinews and bones, and the brain and marrow. Once it becomes insufficient, the body's nourishment becomes imbalanced, leading to a series of discomforts.

TCM emphasizes the concept of the "common origin of the Liver and Kidneys." Deficiency of Kidney Yin can consequently deplete Liver Yin. As the Liver opens into the eyes, insufficiency of Liver Yin worsens symptoms like blurry vision and dry eyes. To address this condition, Erzhi Wan (Two Solstices Pill) from the *Compendium of Medical Formulas* (*Yi Fang Ji Jie*) by the renowned Qing dynasty physician Wang Ang is considered a classic formula for gently tonifying the Liver and Kidneys. Using only two herbal ingredients in combination, it tonifies without causing stagnation, specifically targeting the nourishment of Kidney Yin and Liver Yin, and the supplementation of essence and blood.

The naming of Erzhi Wan (Two Solstice Pills) is well-considered, with the key ingredients—ligustrum lucidum (nüzhenzi) and eclipta prostrata (mohanlian)—harvested at the winter solstice and summer solstice, respectively. The preparation requires meticulous care: after drying in the shade, the ligustrum lucidum is mixed with honey and steamed with wine, then peeled, sun-dried, and ground into powder; the eclipta prostrata is pounded and decocted, then mixed with an equal amount of ligustrum lucidum to form pills. For a decoction, simply take 10 grams of each, boil, and drink the liquid.

It is suitable for the syndrome of liver-kidney yin deficiency with internal heat. You can check for these symptoms: dizziness, blurred vision, insomnia, and vivid dreams (difficulty falling asleep or waking easily); lower back soreness, fatigue, premature graying or hair loss; warmth in the palms and soles, dry mouth and throat, afternoon feverishness, and night sweats; irritability, short temper, and possibly accompanied by decreased appetite, dry stools, and dark yellow urine.

Ligustrum lucidum has a mild medicinal nature, with a bitter and sweet taste that enters the kidney meridian. It can darken hair, strengthen tendons, and calm the five organs. However, as a seed-based herb with moistening intestinal properties, it should be used cautiously by those with spleen-stomach deficiency cold prone to diarrhea. Eclipta prostrata, also known as hedyotis diffusa (lichen), can tonify kidney essence and cool the blood. It addresses issues of blood heat and deficient fire disturbing the liver due to kidney yin deficiency, which affects hair growth. However, due to its cooling nature, those with yang deficiency or spleen deficiency with diarrhea should take note.

It is worth mentioning that the eclipta prostrata harvested at the summer solstice benefits from the abundant yang energy in the natural world at that time, which helps neutralize its cold nature, eliminating the need for additional warming herbs. Additionally, while ligustrum lucidum, goji berries, and mulberries all nourish the liver and kidneys, goji berries have a balanced effect on yin and yang, mulberries also nourish blood, whereas ligustrum lucidum focuses specifically on nourishing the kidneys and liver and consolidating kidney essence, with each suited to slightly different indications.

Erzhi Pill works synergistically with two herbs to replenish yin fluid in the liver and kidney. When essence is sufficient to transform qi, bodily functions recover, thereby improving a haggard and aged appearance. It should be noted that traditional Chinese medicine (TCM) conditioning requires syndrome differentiation. Caution is advised for individuals with spleen-stomach deficiency-cold and yang deficiency with diarrhea, and use under the guidance of a professional physician is recommended.