What is Bupyeong?

Bupyeong is a tiny water plant that floats on ponds. Its Latin name is Spirodela polyrhiza. In English it is called duckweed.

Korean medicine uses the whole dried plant. It was given to make the body sweat and to make it pass more water. Healers used it for itchy rashes, for hives, and for the rash of measles.

Here is the short verdict. No human trials of Bupyeong have been published. Its standing comes from long use, and long use is not proof that a herb works.

How does Bupyeong work?

The honest answer is that no one has shown how Bupyeong works in people.

Old texts say it opens the skin and brings out sweat. They also say it moves water out through the urine. These are ideas from tradition, not measured effects.

Lab work gives a few hints. The plant holds flavonoids (plant pigments that act as antioxidants). In test tubes, some of these calm cells that drive itching and swelling.

Test-tube results often do not carry over to people. Treat them as clues, not proof.

What forms does Bupyeong come in?

The dried whole plant is the usual form.

Most people take it as a tea. The dried herb is boiled in water, then strained.

Powders and capsules are sold too. Herb shops also put it inside mixed Korean and Chinese formulas.

It is sometimes used on the skin. The herb is steeped, cooled, and then dabbed on an itchy patch.

Where it comes from:

Bupyeong is an old and shared East Asian herb.

Korean books list it as Bupyeong. Chinese herb books call it Fu Ping and give it much the same uses. Japanese Kampo knows it too, though it is used less often.

It appears in the Korean classic Donguibogam of 1613. There it is mostly a herb for rashes, fevers without sweat, and puffy swelling.

What does Bupyeong help with?

• Hives and itchy skin rashes: This is the main traditional use in Korea and China. Texts pair it with other herbs for red, raised, itchy skin. No human trial has tested Bupyeong for hives. Lab tests show some of its flavonoids calm cells linked to itching, which is a long way from proof in people.
• The rash of measles: Old texts used it to help a measles rash come out fully. This was a core use before vaccines existed. There is no modern trial support. Measles is a serious illness in children and needs a doctor, not a home herb.
• Mild puffy swelling from held water: Tradition treats Bupyeong as a herb that makes you pass more water. It was given for a puffy face, puffy hands or a puffy belly. No human trial has measured this. New or fast swelling can point to heart, liver or kidney trouble and should be checked by a doctor.
• Early colds with fever and no sweat: Korean and Chinese texts use it at the very start of a cold, when you feel hot but cannot sweat. It was often mixed with mint or other light herbs. No human trial supports this. Colds also get better on their own, which makes any home remedy look helpful.
• Trouble passing urine: Tradition uses it for scant or slow urine that goes with puffiness. There is no trial evidence. Pain, blood, or a sudden stop in passing urine needs medical care the same day.

Which foods are rich in Bupyeong?

1. Farmed water lentils (duckweed grown in clean tanks): sold as a green protein powder in some countries
2. Duckweed leaf protein in animal feed: the same plant family, not a medicine

Practical Tips:

Food duckweed is farmed in tested water and is not the same as a dosed herbal tea.

What are the side effects of Bupyeong?

• Upset stomach or loose stools
• Too much sweating
• Thirst, dry mouth and weakness from fluid loss
• Dizziness or feeling faint when you stand up
• Skin rash or itching from an allergy to the plant
• Exposure to lead, cadmium or arsenic (toxic metals) if the plant was grown or picked in dirty water

Good to know:

Reports of harm are few, but no one has tracked side effects in a proper study. That means the true rate is simply not known.

The most likely problems are mild: a loose stomach, sweating, or feeling dry and weak. These usually settle when you stop.

The serious worry is the source. Duckweed pulls metals out of the water it floats on, so herb from a clean, tested supply matters a great deal.

How much Bupyeong should you take?

• Recommended daily: No modern safe dose has been set, because no trials exist. Korean and Chinese texts use 3 to 9 grams of the dried plant per day. The herb is boiled in water and the tea is split into two or three drinks. Some older texts go a little higher, up to about 10 grams. Start at the low end if a trained practitioner has advised it.
• Best time of day: Daytime is best. It is used to make you pass more water, so a late dose may wake you at night. Keep the last drink several hours before bed.
• With or without food: Between meals is the traditional choice, taken as a warm tea. If it upsets your stomach, take it with a little food instead.
• Time to effect: Unknown, because no trials have measured it. Old texts expected sweating within a few hours of a hot drink. Any effect on a rash or swelling has never been timed in a proper study.
• How long to take it: Tradition uses it for short spells, not for months. A few days to about one week is the usual pattern. Stop and rethink if nothing has changed after a week. See a doctor rather than repeating courses for a rash or swelling that keeps coming back.