What Is Commelina Communis (Asiatic Dayflower or Ya Zhi Cao)

Commelina Communis is commonly known as Asiatic Dayflower or Ya Zhi Cao, which is an annual herb belonging to the family Commelinaceae. It first appeared in <Bencao Shiyi> (Gleanings from the Bencao) around 739 AD.

The plant originated in most parts of East and Southeast Asia and was later introduced to Europe and North America. It is considered an invasive weed in some countries and can harm crops such as wheat, soybeans, corn, and vegetables. Its flowers can be made into cyan pigments for painting.

In summer and autumn each year, people gather the above-ground part of Commelina Communis, rinse them with water, cut them into sections, use them directly or dry them to make them into Chinese herbs.

Commelina Communis contains delphinidin, delphinidin 3-glucoside, awobanin, anthocyanin, commelinin, polypeptide glycosides, and starch. The yellow-green Commelina Communis is the best.

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

In Chinese medicine, Commelina Communis is often used for clear heat and reduce fire, remove toxin, induce diuresis and eliminate edema, relieve fever caused by colds, polydipsia caused by febrile diseases, and sore throat.

Health benefits of Commelina Communis

  • Anti-inflammation, anti-pathogen, anti-bacteria.
  • Relieving sore throat caused by heat toxins.
  • Relieving fever, irritability, and thirst caused by febrile diseases.
  • Relieving high fever and sore throat caused by wind-heat.
  • Promoting urination, eliminating edema, and relieving oliguria, hematuria, difficult and painful urination caused by damp-heat.
  • Treating jaundice, mumps, influenza, meningococcal meningitis, and acute tonsillitis.
  • The topical application after mashing it can clear the heat toxin and treat skin ulcers, abscesses, stye, and erysipelas.

Commelina Communis is used with other Chinese herbs

  • It with Ban Lan Gen (Radix Isatidis) and Xuan Shen (Radix Scrophulariae) can alleviate sore throat caused by heat toxins.
  • It with Pu Gong Ying (Dandelion) and Sang Ye (Mulberry Leaf) to treat upper respiratory infections, bronchitis, and pneumonia.
  • It with Guan zhong (Dryopteris), Huang Qin (Radix Scutellariae), She Gan (Blackberry Lily), and Ban Lan Gen (Radix Isatidis) to treat varicella and upper respiratory infections in children.
  • It with Fu Ping (Duckweed) and Bai Mao Cen (Rhizoma Imperatae) to promote urination, treat edema, oliguria, difficult and painful urination.
  • It with Jin Yin Hua (Flos Lonicerae), Lian Qiao (Fructus Forsythiae), and Bo He (Mentha) can alleviate the persistent high fever caused by wind-heat.
  • It with Shi Gao (Gypsum), Zhi Mu (Rhizoma Anemarrhenae), and Lu Gen (Rhizoma Phragmitis) can alleviate the high fever, irritability, and thirst caused by fever.

Side effects of Commelina Communis

In China and India, it is often used as a vegetable and feed with few side effects.

Precautions of Commelina Communis

  • The dosage of Commelina Communis should be controlled at 15-30g.
  • When using fresh Commelina Communis, the dosage should be controlled at 60-90g.
  • It can be made into decoction or mashed for external use.
  • People with weakness of spleen and stomach should not take it in large doses.
  • People with deficiency-cold in spleen and stomach should not take it.
  • Pregnant women should not take it.