Hai Tong Pi (Cortex Erythrinae)

What Is Hai Tong Pi

Hai Tong Pi commonly known as Cortex Erythrinae is the bark of Erythrina variegata or Erythrina arborescens, which is a thorny deciduous tree belonging to the family Leguminosae. It is a relatively practical Chinese herbal medicine, which first appeared in <Hai Yao Ben Cao> (Materia Medica from the Overseas and Southern) in the early 10th century.

There are about 123 species of Erythrina, which are distributed in tropical and subtropical regions. Among them, most species are for ornamental purposes, and only some species have medicinal value.

Erythrina variegata is commonly known as Indian coral tree. They like strong light, high temperature, and humid environments. They grow well in fertile, well-drained sandy loam soil. They are often planted near coastal streams and parks. They can be found in East Asia, Southeast Asia, East Africa, and northern Australia.

Erythrina variegata

Erythrina arborescens are suitable for growth in subtropical warm climates. They often grow in ravines or grassy slopes at an altitude of 450-2,100 meters. They are distributed in India, Bangladesh, Nepal, Myanmar, Thailand, and China.

In summer and autumn, people peel the bark of Erythrina variegata and Erythrina arborescens, remove impurities, dry them in the sun, cut them into pieces, and make them into Chinese herbal medicines.

Hai Tong Pi contains 3-Demethoxyerythratidinone, erythraline, erythramine, erythrinine, erythratidinone, erysonine, erysotine, erysodine, erysovine, 11-hydroxy- epi- erythratidine, erythratidine, epi- erythratidine, erysodienone, erysotrine, erysopitine, erythrartine, scoulerine, coreximine, 1-reticuline, erybidine, erysovine, stachydrine, indole-3-alkylmamines-hypaphorine, N, N-dimethyltryptophan methyl ester, erythritol, erythrinins A, B, and C, osajin, alpinum isoflavone, linear pyranoisoflavones, robustone, 4-O-methylalpinum isoflavone, erycricstagallin, orientanol B, erystagallin A, stigmasterol, campesterol, stigmoidins A, B, and C, phaseollin, 3-β-acetoxy-B-norcholest-5-ene, docosanoic methyl ester, 29-norcycloartenol, β-sitosterol, archidate, capric acid, abyssinone V, eryvarinols A and B, euchrenone b10, isoerysenegalensein E, wighteone, laburnetin, lupiwighteone, erythrodiol, oleanolic acid, epilupeol, 6-hydroxygenistein, erythrabyssin II, dihydrofolinin, octacosyl ferulate, wax alcohol, wax acids, alkyl ferulates, alkyl phenolates, amino acids, and organic acids.

Generally, Hai Tong Pi with thin bark, more spikes, and a light fragrance is preferred.

According to <Compendium of Materia Medica>, the medicinal nature of Hai Tong Pi is relatively neutral, with a bitter and pungent taste. It has a therapeutic effect on the pathological changes of the liver meridian.

In traditional Chinese medicine, it is often used to expel wind and dampness, activate meridians and relieve pain, kill parasites and relieve itching, and treat rheumatic arthralgia, spasm of limbs, aching pain in waist and knees, limb paralysis, disadvantageous flexion and extension of joints, fractures, knee osteoarthritis, protrusion of the lumbar intervertebral disci, cervical spondylosis, periarthritis humeroscapularis, talalgia, varicose ulcer of the lower extremity, fever, bacterial infection, insomnia, helminthiasis, cough, traumatic low back pain, scabies, and eczema.

There are about 50 kinds of traditional Chinese medicine prescriptions containing it, such as Tou Gu Zhen Feng Wan, Guan Jie Ke Bi Wan, Feng Tong An Capsules.


  • Anti-inflammation, inhibiting xylene-induced ear swelling and glacial acetic acid-induced increased capillary permeability in mice.
  • Increasing the pain threshold, prolonging the latency of hot plate reaction in mice, and reducing the number of writhing in mice caused by acetic acid.
  • Anti-oxidation, scavenging DPPH free radicals and inhibiting lipid oxidation.
  • Transient reduction in blood pressure in experimental cats and rats.
  • Inhibiting urinary calcium excretion and increasing serum calcium level in ovariectomized rats.
  • Suppressing the high rate of bone turnover induced by estrogen deficiency, inhibiting bone loss, and improving the biomechanical properties of bone in ovariectomized rats [1].
  • Expelling wind and dampness, activating meridians, treating rheumatic arthralgia, spasm of limbs, aching pain in waist and knees, and limb paralysis.
  • Expelling wind and drying dampness, treating itching caused by eczema and scabies.
  • It cooperates with pentobarbital sodium to prolong the sleep time of experimental mice.
  • Inhibiting the proliferation of liver cancer HepG-2 cells, liver cancer BEL-7402 cells, rectal cancer HCT-8 cells, and lung cancer A549 cells.
  • Its total alkaloids can induce relaxation of isolated rabbit ileal smooth muscle and inhibit the spontaneous rhythmic contraction of isolated rat uterus [2].
  • The findings indicate that erycristagallin has a potential as potent phytochemical agent for prevention of dental caries by inhibiting the growth of cariogenic bacteria and by interfering with incorporation of glucose responsible for production of organic acids [3].
  • Experiments have confirmed that its hydroalcoholic extract has anxiolytic and antidepressant properties in mice [4].


Side Effects

  • Animal studies have shown that its extracts do not show abnormalities when given orally, but intraperitoneal injection at certain doses can cause death in animals.
  • At present, there are no reports of serious adverse reactions in the prescribed doses of Hai Tong Pi.

Precautions and Warnings

  • The dosage of Hai Tong Pi should be controlled at 5-15g.
  • It can be made into decoctions, medicinal liquors, or lotions.
  • People who are allergic to Hai Tong Pi should not take it.
  • It should not be taken at the same time as potassium iodide.
  • People with blood deficiency should not take it.
  • Pregnant and breastfeeding women should take it under the guidance of a doctor.