Zi Cao (Radix Arnebiae or Arnebia Root)

What Is Zi Cao

Zi Cao also known as Radix Arnebiae or Arnebia Root is the root of Arnebia euchroma or Arnebia guttata, which is a perennial herb belonging to the family Boraginaceae. It has a medicinal history of more than 2,000 years.

Arnebia euchroma often grows in mountains, grasses, dry stone slopes, valleys, and shrubs at an altitude of 2,500-4,200 meters. It is distributed in China’s Xinjiang, Tibet, Nepal, Pakistan, Afghanistan, Iran, and Russia. 70% of the world’s medicinal Zi Cao materials come from this species.

Arnebia guttata often grows in the Gobi, rocky mountain slopes, and lakeside gravel lands at an altitude of 280-4,200 meters. It is distributed in Pakistan, Mongolia, Kashmir, India, Russia, Afghanistan, and China. It is not currently cultivated by artificial introduction.

Arnebia euchroma

Lithospermi radix is also called Zi Cao in China and is the root of Lithospermum erythrorhizon. It is a Chinese herbal medicine with various antiviral and biological activities. Earlier, it was used interchangeably with the Radix Arnebiae.

Every spring and autumn, people gather the roots of Arnebia euchroma or Arnebia guttata, remove their impurities, wash them with water, cut them into thick pieces, dry them in the sun, and make them into Chinese herbal medicines.

Zi Cao contains shikonin, deoxyshikonin, acetylshikonin, propionylshikonin, isobutylshikonin, isovalerylshikonin, β-hydroxy isovaleryl shikonin, β,β’-dimethylacryloyl shikonin, α-methyl-n-butyryl shikonin, 3,4-dimethylpentene-3-acyl shikonin, alkannin, alkannan, phenolic acids, benzoquinones, fatty acids, alkaloids, and polysaccharides.

Generally, a purple-red or purple-brown Zi Cao with thick skin, small woody core, and yellow-white or yellow cross-section is preferred.

According to <Compendium of Materia Medica>, the medicinal nature of Zi Cao is relatively cold, with a sweet and salty taste. It has a certain therapeutic effect on the pathological changes of the heart and liver meridians.

In traditional Chinese medicine, Zi Cao is often used to clear heat and cool blood, promote blood circulation and eruptions, remove toxin, treat eczema, pityriasis rosea, uterine erosion, urethral stricture, burns, hepatitis, oral mucosal disease, psoriasis, phlebitis, allergic purpura, refractory ulcer, suppurative otitis media, and vaginitis.

About 50 kinds of traditional Chinese medicine prescriptions contain it, such as Jing Wan Hong Ruan Gao, Bai Shi Wan, and Shengji Yuhong Gao.


  • Anti-inflammation, inhibiting xylene-induced ear swelling in mice.
  • Inhibiting the expression of mast cells and TNF-α, having an anti-allergic effect.
  • Scavenging DPPH free radicals and inhibiting lipid oxidation.
  • Inhibiting the expression of fat transcription factors and the accumulation of fat in cells.
  • Inhibiting platelet aggregation and preventing atherosclerosis and thrombosis.
  • Promoting the proliferation of T lymphocytes, enhancing the phagocytic function of peritoneal macrophages, and improving immunity.
  • Reducing the acute liver injury induced by concanavalin A, D-galactosamine, or acetaminophen and protecting the liver.
  • Clearing heat, treating purple-black macules, and rashes caused by warm-toxins.
  • Promoting eruptions and relieving sore throat.
  • Cooling blood, treating hematemesis and epistaxis caused by blood heat.
  • Removing heat toxins, relieving skin swelling and pain, and treating sores and carbuncles caused by heat toxins.
  • Promoting skin wound healing, treating skin ulcers, burns, and scalds.
  • Inhibiting human papillomavirus, herpes virus, hepatitis B virus, HIV-1 virus, parainfluenza virus, and influenza A virus.
  • Inhibiting the proliferation of MCF-7 breast cancer cells, HCC liver cancer cells, A549 lung cancer cells, prostate cancer cells, and AGS human gastric cancer cells.
  • Inhibiting Staphylococcus aureus, Escherichia coli, Bacillus subtilis, typhoid bacillus, dysentery bacillus, Pseudomonas aeruginosa, hemolytic streptococcus, Proteus, Candida albicans.
  • Reducing the concentration of serum follicle-stimulating hormone, luteinizing hormone, and estradiol in the body, and inhibiting fertility. Its anti-fertility function is reversible. Through the metabolism of drugs, the body can restore fertility.
  • Studies have found that the decoction of the root of Arnebia euchroma can excite the heart.


Side Effects

  • Some studies report that it contains a variety of hepatotoxic alkaloids, which may cause liver damage.
  • Overdose it may cause nausea or loose stools.

Precautions and Warnings

  • The dosage of Zi Cao should be controlled at 5-10g.
  • It can be made into decoctions, pills, ointments, or mashed for external use.
  • People who are allergic to Zi Cao should not take it.
  • Patients with a complete measles outbreak should not take it.
  • Patients with weakness of the spleen and stomach should not take it.
  • Patients with loose stools should not take it.
  • Pregnant women, women preparing for pregnancy, and breastfeeding women should not take it.