Ya Zhi Cao (Asiatic Dayflower or Commelina Communis)

What Is Ya Zhi Cao

Ya Zhi Cao is commonly known as Asiatic Dayflower or Commelina Communis, which is an annual herb belonging to the family Commelinaceae. It first appeared in <Ben Cao Shi Yi> (Supplements to Newly Revised Materia Medica) around 739 AD.

This plant likes a warm, humid climate and can grow in slightly humid soil. They often grow in places such as ditches, roadsides, ridges, vegetable fields, etc. They are distributed in China, Vietnam, North Korea, Japan, the Russian Far East, and North America.

They are recognized as invasive weeds in some countries, which can harm crops such as wheat, soybeans, corn, vegetables, and so on. Its flowers can be made into cyan pigments.

In summer and autumn, people gather the above-ground part of Commelina Communis, wash them with water, cut them into sections, use them directly or dry them in the sun and make them into Chinese herbal medicines.

Commelina Communis

Ya Zhi Cao contains flavocommelin, flavocommelitin, friedelin, loliolide, delphinidin, awobanin, hydroxycinnamic acid, ginkgolide A, ginkgolide B, sciadopitysin, luteolin, kaempferol, p-hydroxyben-zaldehyde, syringaldehyde, acetovanillone, protocatechuic acid, ρ-hydroxybenzoic acid, palmitic acid, β-sitosterol, stigmasterol, daucosterol, isoorientin, alkaloids, and polypeptide glycosides.

Generally, yellow-green Ya Zhi Cao is preferred.

According to <Compendium of Materia Medica>, the medicinal property of Ya Zhi Cao is relatively cold, with a slightly sweet and bland taste. It has certain therapeutic effects on the pathological changes of the lung, stomach, and small intestine meridians.

In traditional Chinese medicine, it is often used to clear heat and purge fire, remove toxins, induce diuresis and alleviate edema, treat chickenpox, upper respiratory tract infection, bronchitis, pneumonia, neuropathic vomiting, prostate hypertrophy, acute tonsillitis, acute viral hepatitis, hemorrhagic Conjunctivitis, mumps, pelvic inflammatory disease, herpes zoster, stye, flu, sore throat, malaria, epistaxis, hematuria, and erysipelas.

There are about 30 kinds of Chinese medicine prescriptions containing it, such as Fufang Yinhua Jiedu granules, Yan Ning granules, and Ya Jie Pian.


  • Anti-inflammation, inhibiting xylene-induced ear swelling in mice.
  • Increasing the pain threshold and inhibiting the pain caused by the mouse hot plate experiment and glacial acetic acid experiment.
  • Anti-oxidation, scavenging DPPH free radicals and hydroxyl free radicals.
  • Inhibiting the activity of α-glucosidase and reducing blood glucose levels after meals.
  • Reducing liver damage induced by CCL4 or alcohol and protecting the liver.
  • Clearing heat and purging fire, treating the early symptoms of common cold due to wind-heat.
  • Treating high fever and polydipsia caused by heat attacking qifen.
  • Removing heat toxins, treating swelling and sore throat, carbuncles, and skin ulcers.
  • Promoting urination and eliminating edema, relieving oliguria, hematuria, and painful urination caused by damp-heat.
  • Inhibiting Staphylococcus aureus, Candida albicans, Shigella dysentery, Bacillus subtilis, Escherichia coli.
  • Its petroleum ether and formaldehyde extract can relieve the cough caused by ammonia mist in mice.
  • Studies have found that its water extract has a significant inhibitory effect on cytopathic changes caused by influenza viruses in vitro.


Side Effects

At present, there are no reports in the literature that Ya Zhi Cao has toxic effects, and there are no reports of serious adverse reactions when it is taken according to the prescribed dose.

If you need to take it for a long time, please consult a professional doctor and formulate a reasonable medication plan.

Precautions and Warnings

The dosage of Ya Zhi Cao should be controlled at 15-30g.
When using fresh Ya Zhi Cao, the dosage should be controlled at 60-90g.
It can be made into decoctions or mashed for external use.
People who are allergic to Ya Zhi Cao should not take it.
People with deficiency-cold in the spleen and stomach should not take it.
Pregnant and breastfeeding women should take it under the guidance of a doctor.
Children, the elderly, and the infirm should take it under the guidance of a doctor.