Scouring Rush Herb

Chinese
木贼
Pinyin
Mu Zei
Latin
Herba Equiseti Hiemalis

TCM Properties

Taste
acrid, bitter
Temperature
slightly cold
Channels
Liver, Lung

Traditional Use

Primary Actions

  • Disperses wind-heat and clears the eyes - Mu Zei is primarily used for red, swollen, painful, tearing eyes when wind-heat or Liver heat rises upward to the head.
  • Improves vision and removes superficial visual obstruction - it is classically selected for nebula, corneal haze, pterygium-style overgrowth, blurred vision, and persistent cloudiness on the eye surface.
  • Vents wind-heat from the head - when eye redness is accompanied by mild headache or irritability from upward-moving heat, Mu Zei helps direct the disturbance outward.
  • Supports treatment of upper-body heat with bleeding or irritation - later materia medica sometimes extends its use to hemorrhoidal bleeding or hematemesis associated with heat, although its modern use remains overwhelmingly eye-focused.

Secondary Actions

  • Mu Zei is usually paired with other eye herbs such as Ju Hua, Chan Tui, Mi Meng Hua, or Jue Ming Zi because it is best at dispersing the superficial wind-heat component rather than nourishing deficiency.
  • The rough silica-rich stems are broken or bundled before decoction, and the herb is typically used for short eye-focused courses rather than long-term tonic therapy.

Classic Formulas

  • Mu Zei San - traditional eye-focused powder or decoction strategy for superficial visual obstruction, pterygium, or lingering wind-heat irritation.
  • Mu Zei with Ju Hua and Chan Tui - common wind-heat eye combination for red, painful, tearing eyes with light sensitivity or headache.
  • Mu Zei with Mi Meng Hua and Jue Ming Zi - vision-clearing pairing for corneal haze, glare, blurred vision, or superficial eye opacity.
  • Mu Zei with Sang Ye and Bo He - exterior-releasing combination when eye redness appears together with wind-heat headache or early-stage upper-body heat.

Classical References

  • Later materia medica classifies Mu Zei among herbs that disperse wind-heat upward and benefit the eyes, especially when there is redness, pain, or superficial visual obstruction.
  • Traditional teaching particularly remembers Mu Zei for tui yi-style eye cloudiness and pterygium-like overgrowth, which explains why it appears more often in ophthalmic than in systemic formulas.
  • Standard modern herbology texts keep Mu Zei in the exterior-releasing category but note that its clinical identity is much more eye-specific than that label alone suggests.

Modern Research

Active Compounds

  • Phenolic compounds and flavonoids - the dominant antioxidant fraction identified in Equisetum hyemale extracts
  • Phenyl glycosides including 2-(sophorosyl)-1-(4-hydroxyphenyl)ethanone - distinctive constituents isolated from the aerial parts
  • Sterols - part of the mixed lipophilic fraction described in wound-healing and extract-characterization studies
  • Lignans and phenylpropanoids - supportive constituents reported in modern phytochemical screening
  • Silica- and mineral-rich structural fraction - a traditional hallmark of horsetail species, although pharmacologic work now focuses more on the phenolic profile

Studied Effects

  • Ethanolic and methanolic extracts of Equisetum hyemale showed antioxidant activity and notable antifungal activity against Trichophyton rubrum and Microsporum canis, supporting part of the herb's traditional anti-irritation and external-use reputation (PMID 25587637).
  • A 40% ethanolic extract accelerated wound healing in diabetic rats, increased IL-10, inhibited MCP-1 release, limited Staphylococcus aureus and Escherichia coli growth, and enhanced fibroblast collagen synthesis (PMID 37111271).
  • A 2025 phytochemistry and ADMET study reported strong ABTS radical-scavenging activity but only weak antibacterial activity, while also finding moderate cytotoxicity in some cancer cell lines and short-exposure toxicity in C. elegans, arguing for caution with concentrated extracts (PMID 41471390).

PubMed References

Safety & Interactions

Contraindications

  • Blurred vision from Liver-Kidney deficiency or Blood deficiency without wind-heat or superficial obstruction
  • Pronounced Qi and fluid depletion without an exterior or eye-heat component

Cautions

  • Long-term heavy use of horsetail-family herbs may contribute to thiamine depletion in animal data and is not appropriate as unsupervised chronic self-treatment.
  • Modern extract studies found moderate in vitro cytotoxicity and short-exposure toxicity in C. elegans, so concentrated extract products deserve more caution than traditional short-course decoctions.
  • Its light, dispersing, and mildly drying nature can aggravate depletion or frequent urination in sensitive patients if overused.
  • MSK page not found - drug interaction data not available from Memorial Sloan Kettering integrative medicine database

Conditions