What is seojanggyeong?

Seojanggyeong is a single herb used in Korean medicine. It is the dried root and root stalk of the plant Cynanchum paniculatum. In English it is called paniculate swallowwort root.

Healers have long used it for pain. Folk use covers sore joints, belly pain, toothache and itchy skin. It was also laid on the skin after snake and insect bites.

The proof in people is thin. Nearly all of the research so far is lab and animal work. Long use in a tradition is not proof that a herb works, so read what follows with that in mind.

How does seojanggyeong work?

No one has shown how it works in people. The best guess comes from lab dishes and animal tests.

Its best known active part is paeonol. In animals, paeonol eased pain and calmed swelling (puffiness and heat in body tissue). It also seemed to quiet some immune cells that drive itching.

Other lab work hints at a mild calming effect on the body. None of this has been shown in people. Treat the whole picture as a theory, not a fact.

What forms does seojanggyeong come in?

You will most often see the dried, sliced root. It is boiled in water to make a tea, called a decoction. Powders, pills and alcohol extracts (tinctures) are also sold.

It is used on the skin too. Folk healers soaked the root in wine, or crushed it fresh, and put it on bites and rashes.

In Korean practice it is rarely used alone. It is usually one herb in a mixed formula.

Where it comes from:

Use of this root goes back about two thousand years in East Asian medicine. Old Chinese texts list it as xu chang qing.

Korean doctors took it up and used it for pain, itch and bites. It still appears in Korean and Chinese herb books today.

What does seojanggyeong help with?

• Joint and muscle pain: This is the most common folk use. Animal tests show paeonol can dull pain signals. No published human trial tests this root for joint or muscle pain, so the benefit in people is unknown.
• Itchy skin and eczema-type rashes: Korean and Chinese herbalists used it for hot, itchy skin. Lab work shows paeonol can calm cells linked to itch. There is no good human trial, and a rash can also be an allergy to the herb itself.
• Toothache: Traditional use only. The root was chewed or held near the sore tooth. Tooth pain usually means decay or an abscess (a pocket of pus), and that needs a dentist, not a herb.
• Belly pain and cramps: Old texts list it for cramping belly pain. Animal work hints at a mild easing of muscle spasm. No human study backs this, and lasting belly pain needs checking by a doctor.
• Skin care after snake or insect bites (traditional use only): The fresh crushed root was placed on bites. There is no proof it works, and it does nothing against venom. A snake bite is a medical emergency — go to hospital straight away.

Which foods are rich in seojanggyeong?

This is a medicinal root, not a food. You will not get it from meals.

What are the side effects of seojanggyeong?

• Nausea or stomach upset
• Loose stools
• Dizziness
• Headache
• Feeling sleepy
• Skin rash or itch from an allergy to the plant
• Unknown effects at high doses

Good to know:

We have no good count of how often side effects happen, because no human trials have been done. Most reports are mild stomach upset and dizziness. Stop taking it and get advice if you feel unwell, and stop at once if you get a rash, swelling or trouble breathing.

How much seojanggyeong should you take?

• Recommended daily: No safe or proven dose has been set by human trials. In traditional Korean and Chinese practice, 3 to 10 grams of the dried root per day is boiled as a tea. People usually split that into two or three cups. The plant is added near the end of the boil, so strength varies a lot. Take it only with guidance from a trained practitioner.
• Best time of day: Split the day's amount into two or three doses, spread morning and evening. If it makes you sleepy, take it in the evening only.
• With or without food: Take it with or just after food. This lowers the chance of nausea and stomach upset.
• Time to effect: Not known from trials. In traditional use, people look for some easing of pain within a few hours to a few days.
• How long to take it: Traditional use is short. Plan on two to four weeks, then stop and review. If your pain or rash has not eased by then, see a doctor instead of taking more.