What is buhaeseok (haebuseok)?

Buhaeseok is pumice. It is a light, frothy rock thrown out by volcanoes. Korean medicine grinds it to a powder and uses it as a single drug.

It is used most often for a cough with thick, sticky mucus that is hard to bring up. It is also a folk remedy for lumps in the neck and for stones and burning pain when you pass urine.

The modern evidence is thin. We found no human trials of pumice for any of these uses, so no one can say it works. Long use in a tradition is not proof of effect, and that point applies to everything below.

How does buhaeseok (haebuseok) work?

No one has shown how pumice acts in the body, and it may not act at all.

In the old East Asian system of ideas, buhaeseok is cool, salty and sinking. It is said to soften hard lumps and thin sticky phlegm (thick mucus) so that a cough can clear it. Those are ideas from tradition, not measured drug actions.

Pumice is mostly silica, a rock mineral that barely dissolves. Most of a dose you swallow likely passes through the gut and out again. Any effect on the lungs from a rock taken by mouth is unproven.

What forms does buhaeseok (haebuseok) come in?

The usual form is a fine grey powder made by grinding washed rock.

Some shops sell a calcined form. This means the rock is heated in a fire first, then crushed. Practitioners mostly add the powder to a mixed formula rather than give it alone.

In a decoction (a boiled water brew) the grit is tied in a cloth bag and boiled longer than the herbs. Pumice is also pressed into pills and mixed powders. It is not sold as a standard capsule supplement in most countries.

Where it comes from:

Chinese texts list pumice as fu hai shi, which means floating sea stone. Korean medicine took the drug in and calls it buhaeseok or haebuseok.

It appears in East Asian materia medica books from about the Song era onward. It sits in the small group of phlegm-clearing minerals.

In Korea it was never a headline herb. It was used inside mixed formulas, rarely on its own.

What does buhaeseok (haebuseok) help with?

• Cough with thick, sticky phlegm (thick mucus): This is the main traditional use. Practitioners give it when a cough is dry-sounding, hard and brings up thick yellow mucus. No human trial has tested pumice for cough, so we cannot say it helps.
• Goitre and neck lumps (a swollen thyroid gland or swollen glands in the neck): Old texts group pumice with salty minerals said to soften hard swellings. There is no trial evidence behind this. A lump in the neck needs a doctor, because some causes are serious and treatable.
• Urinary stones (hard bits that form in the kidney or bladder): Tradition uses it to ease hot, gritty, painful urination. No human study supports this. Stones can block the kidney, so do not self-treat them.
• Hot, painful or difficult urination: Used in old formulas for burning urine. Modern proof is absent. Burning urine is usually an infection, which needs testing and often antibiotics.

Which foods are rich in buhaeseok (haebuseok)?

Pumice is volcanic rock. It is not found in any food and has no place in cooking.

What are the side effects of buhaeseok (haebuseok)?

• Constipation
• Nausea or stomach ache
• A gritty, chalky feel in the mouth and throat
• Poor appetite
• Coughing, wheezing or sore eyes if you breathe in the dry powder
• Reduced effect from other medicines taken at the same time
• Possible build-up of trace heavy metals such as lead or arsenic with long use

Good to know:

Most reported problems are mild gut ones, and they settle when you stop.

The two real worries are different. Breathing the dry dust can harm the lungs, and long use of an unpurified mineral can add to your body's load of heavy metals. Neither has been measured properly in people taking pumice as a medicine, which is itself a reason for care.

How much buhaeseok (haebuseok) should you take?

• Recommended daily: No safe or useful dose has been set by modern research. Classical Korean and Chinese texts give 9 to 15 g boiled in water, or 1.5 to 3 g of the plain powder. The grit is normally tied in a cloth bag and boiled longer than the other herbs. It is a practitioner's drug, not a self-care one. Do not work out your own dose from a bag of ground rock.
• Best time of day: Usually split into two or three doses across the day, as part of a warm brew.
• With or without food: Usually taken between meals in the traditional way. Taking it with food may ease stomach upset, but it can also make the gut absorb your other medicines less well, so keep it well away from any tablet you take.
• Time to effect: Unknown. Traditional practice expects a change in a cough within days, but no study has measured this.
• How long to take it: Traditional use is short. It is given for days to a few weeks while a cough is thick and stubborn, then stopped. Stop and get checked if nothing has changed after two weeks. There is no evidence for taking it month after month, and long use raises the worry about heavy metals building up.