Mu Zei (Scouring Rush or Rough Horsetail)

What Is Mu Zei

Mu Zei is also known as Scouring Rush, Rough Horsetail, Shave Grass, or Equisetum hiemale, which is a perennial evergreen herb belonging to the family Equisetaceae. It first appeared in <Jia You ben cao> (Materia medica of Jia You reign) in the Song Dynasty (around 1,057-1,060 AD).

Equisetum hiemale likes a dark and humid environment. They often grow in riparian wetlands, streams, or weeds at an altitude of 100-3,000 meters. They are distributed in China, Japan, the Korean Peninsula, Russia, Europe, North America, and Central America.

This plant has certain economic and medicinal value. In the early days, it was used as a diuretic by Indigenous peoples of the Plateau. In Japan, they are traditional polishing materials that have similar functions to fine sandpaper.

Equisetum hiemale

In summer and autumn, people gather the above-ground part of Equisetum hiemale, remove impurities, dry them in the sun or dry them in the shade, cut them into sections, and make them into Chinese herbal medicines.

Mu Zei contains apigenin, quercetin, kaempferol, luteolin, kaempferol, ferulic acid, caffeic acid, vanillic acid, p-hydroxybenzoic acid, p-methoxycinnamic acid, fumaric acid, methyl glutarate, m-methoxycinnamic acid, lipids, alkaloids, volatile oils, protein, polysaccharides, pigments, and some trace elements.

According to <Compendium of Materia Medica>, the medicinal property of Mu Zei is relatively neutral, with a sweet and bitter taste. It has a certain therapeutic effect on the pathological changes of the liver and lung meridians.

In traditional Chinese medicine, it is often used to dispel wind and heat, improve vision and remove nebula, and treat condyloma acuminatum, flat warts, jaundice hepatitis, colds, infantile malnutrition, urinary stones, blood in urine, blood in the stool, hematuria, nosebleeds, high blood pressure, oral mucosal ulcers, dysentery, and lead poisoning.

There are about 50 kinds of Chinese medicine prescriptions containing it, such as Long Ze Xiong Dan Capsules, Bo Yun Tui Yi Wan, and Huanglian Yanggan Wan.


  • Anti-oxidation, scavenging hydroxyl radicals, superoxide anion radicals, and DPPH free radicals.
  • Inhibiting adenovirus, polio type I virus, and parainfluenza type III virus.
  • Reducing the blood sugar content of alloxan diabetic mice.
  • Reduce the total cholesterol, low-density lipoprotein, triglyceride content in the serum, and increase the high-density lipoprotein content.
  • Reducing serum total cholesterol, low-density lipoprotein, triglyceride content, and increasing high-density lipoprotein content.
  • Inhibiting platelet aggregation induced by adenosine diphosphate, collagen, or thrombin, and reducing the weight of thrombus.
  • Inhibiting hepatocyte apoptosis and improving food-induced fatty liver in rats.
  • Increasing coronary blood flow, slowing down heart rate, dilating blood vessels, and lowering blood pressure.
  • Dispelling wind and heat, treating redness, swelling, and pain of the eyes, lacrimation induced by irritation of the wind, nebula caused by wind-heat attacking the upper.
  • Clearing liver heat, treating red and swollen eyes caused by liver heat.
  • Shortening the time of bleeding and blood clotting, and treating traumatic bleeding, gastrointestinal bleeding, gynecological bleeding, and blood in the stool.
  • Its alcohol extract cooperates with pentobarbital sodium to extend the sleep time of experimental mice.
  • Inhibiting the growth of HepG2 cells of liver cancer and Hela cells of cervical cancer.
  • Its chloroform extract has a diuretic effect.
  • Its alkaloids have certain inhibitory effects on Escherichia coli, Bacillus subtilis, and Staphylococcus aureus.
  • Studies have found that its n-butanol extract regulates the expression of Fas and FasL genes in aortic smooth muscle cells in the early stage of atherosclerosis, promotes smooth muscle cell apoptosis, and blocks atherosclerosis.


Side Effects

Studies have shown that horsetail has very low toxicity, but overdose may cause discomfort.

Taking it in excess may cause hyperkalemia.

A small percentage of people taking it may experience fatigue, cold limbs, muscle pain, slowed heartbeat, nausea, vomiting, loss of appetite, and diarrhea.

Precautions and Warnings

  • The dosage of Mu Zei should be controlled at 3-9g.
  • It can be made into decoctions or ground into powder for external use.
  • People who are allergic to Mu Zei should not take it.
  • It should not be used with drugs containing potassium iodide.
  • People with the deficiency of qi and blood should not take it.
  • Pregnant women and breastfeeding women should take it under the guidance of a doctor.