Educational information, not medical advice — ask your doctor or midwife.
Er Zhi Wan is a Chinese herbal formula. It is also known as Two-Solstice Pill. It is listed here as a single item (one TCM formula), not as a loose mix of separate herbs.
The formula holds just two herbs. One is the fruit of glossy privet (Nu Zhen Zi). The other is the herb eclipta (Mo Han Lian, also called Han Lian Cao).
Each herb is picked at a solstice, the longest and shortest days of the year. That is where the name Two-Solstice Pill comes from.
Chinese medicine uses it for a pattern called liver and kidney yin deficiency (a dry, over-heated, worn-down state). In day-to-day terms, people take it for dizziness, ringing in the ears, a sore low back and knees, dry eyes, night sweats and early grey hair.
Here is the honest bottom line. The formula has a long record of use in China, but good human trials are almost absent. Long traditional use is not proof that something works, and that caveat applies to everything on this page.
No one has shown clearly how Er Zhi Wan works in the body.
The traditional idea is simple. Chinese medicine says the formula feeds yin, the cooling and moistening side of the body. When yin runs low, the body is said to run dry and hot, which is linked to night sweats, dry eyes and a sore low back.
Lab and animal work gives some hints, but no firm answer. In test tubes, both herbs act as antioxidants, meaning they mop up unstable molecules that can damage cells. Animal studies have looked at bone cells, liver cells and immune cells.
Those findings are early. They come from dishes and rodents, not people. They do not tell you what the pills will do in your body.
Honey pills (mi wan) are the classic form. These are small, soft, dark pills.
You may also find:
Water pills or tablets, made from powdered herbs.
Capsules holding powdered herb or a dried extract.
Loose dried herbs, simmered in water at home to make a tea (a decoction).
Liquid tinctures or ready-made granules you stir into hot water.
Quality varies. Some imported herbal pills have been found to hold heavy metals or hidden drug ingredients. Buy from a seller who tests each batch and shows you the results.
Er Zhi Wan appears in Chinese formula books from the 1600s. It is most often credited to Wang Ang, who set it down in his collected formulas in 1682.
It became a staple for yin deficiency of the liver and kidney. Chinese doctors still use it today, often with other formulas rather than alone.
Its standing rests on centuries of written use in one tradition, not on modern trials.
See a doctor if dizziness, ringing in the ears or night sweats are new, getting worse, or affect only one ear. These can point to a problem that needs proper testing.
Stop the formula and see a doctor if you get yellow skin or eyes, dark urine, pain in your upper right belly, or unusual bruising or bleeding.
Get urgent help if you have a spreading rash, swelling of the face, lips or tongue, or trouble breathing.
Always tell your doctor and pharmacist that you are taking this formula, especially before any surgery.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Er Zhi Wan is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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