What is Mazu?

Mazu is the dried gall (a hard, round growth) that forms on the twigs of the oak tree Quercus infectoria after a small wasp lays its eggs there. It is a single drug in the Persian and Unani traditions, not a mixture. It is used mainly as an astringent, meaning it makes tissue draw together and tighten.

Traditional practitioners use it as a mouthwash or gargle for sore gums and throat, as a wash or ointment for weeping skin and piles (haemorrhoids), and in small internal doses for loose stools. It is very rich in tannins, the same bitter, puckering compounds found in strong black tea.

The honest verdict: Mazu has deep and wide traditional standing, but good human trials are essentially missing. Long traditional use is not proof that something works, and that gap applies to every use listed on this page.

How does Mazu work?

Mazu is thought to work almost entirely through its tannins. Tannins bind to proteins on the surface of skin, gums and gut lining, forming a thin protective layer that feels tight and dry.

That same binding action may reduce oozing, slow minor bleeding from surface tissue and firm up loose stools. Laboratory work also shows the extract slows the growth of several bacteria and fungi in a dish.

These are plausible explanations, not proven ones. What happens in a test tube often does not happen in a person, and this has not been properly tested in people.

What forms does Mazu come in?

Mazu is sold whole, as a coarse powder, or as a dark extract. Whole galls are usually crushed or ground just before use.

Common preparations include a decoction (simmered water extract) used as a gargle or wash, a powder dusted onto weeping skin, and ointments or suppositories for piles. Powder is also blended into tooth powders and mouthwashes.

Internal use, when it happens at all, is small amounts of powder in water or honey. Concentrated tannic acid extracts sold for internal use are a different and riskier product.

Where it comes from:

Mazu appears in Persian and Unani medicine from the classical period onward, and is described in the works of Avicenna (Ibn Sina) and later Unani compendia as a strong drying and binding drug. It also has a long record in Ayurveda as majuphal and in Chinese medicine as mo shi zi.

It was widely traded, and for centuries the same galls were the main source of iron gall ink and of tanning material for leather. Its medicinal reputation in every tradition rests on the same property: it tightens and dries tissue.

What does Mazu help with?

• Sore, bleeding or inflamed gums: This is the most common traditional use, as a diluted rinse. The tannins tighten gum tissue and reduce oozing, which is consistent with how astringents behave. Human trial evidence for Mazu specifically is very thin, so treat it as a comfort measure, not a treatment for gum disease.
• Sore throat (used as a gargle): Persian and Unani texts recommend a cooled decoction as a gargle. It may feel soothing and drying. It does not treat the infection behind a sore throat, and it should never be swallowed in quantity.
• Mouth ulcers: Traditionally dabbed or rinsed on to dry the sore and ease pain. Any relief is likely short and local. Ulcers that last more than three weeks need a dentist or doctor, not a home rinse.
• Short-term diarrhoea: Small internal doses are a classical Unani use, on the idea that tannins firm the stool. Evidence in people is absent. Because dehydration is the real danger in diarrhoea, fluids and salts matter far more, and blood in the stool or fever means you need medical care.
• Piles (haemorrhoids): Used as a sitz bath, ointment or suppository to shrink and dry swollen tissue. This is a well-established traditional use across several traditions. No reliable human trial has confirmed it, and bleeding from the back passage always needs a proper diagnosis.
• Weeping or oozing skin patches: A cooled decoction is used as a compress to dry out weeping eczema or minor infected skin. Laboratory work shows activity against some skin bacteria and fungi. Whether that helps a real skin condition has not been tested properly in people.
• Minor surface cuts and grazes: Powder or wash is traditionally applied to help minor surface bleeding stop. Use it only on small, clean, shallow grazes. Deep wounds, animal bites and anything still bleeding after ten minutes need medical attention.

Which foods are rich in Mazu?

1. Strong black tea: the closest everyday source of the same gallotannins
2. Red wine and unripe persimmon: high in astringent tannins
3. Pomegranate peel: a traditional tannin-rich astringent in the same regions
4. Acorns and oak bark: same tree family, same tannin chemistry

What are the side effects of Mazu?

• Strong bitter, puckering taste and a dry mouth
• Nausea or stomach pain if swallowed
• Constipation with repeated internal use
• Vomiting after large internal doses
• Staining of teeth, tongue or fabric (it is a dye)
• Skin irritation or a dry, tight feeling where applied
• Reduced iron absorption from food and supplements
• Liver injury reported after large or prolonged intake of concentrated tannic acid

Good to know:

Used as a diluted external rinse or wash for a few days, Mazu is generally well tolerated, and the usual complaints are taste, dryness and staining.

The risks rise sharply when it is swallowed. Very high tannin levels can irritate the stomach, block iron absorption and, in large or prolonged doses, damage the liver.

That liver risk is why this page carries a caution tier rather than a routine one. Treat internal use as something that needs professional supervision.

How much Mazu should you take?

• Recommended daily: There is no established, tested dose for Mazu, and no official standard exists. Traditional external use is roughly 5 to 10 grams of crushed gall simmered in about 500 ml of water, then cooled and strained, used as a gargle, wash or sitz bath. Traditional internal use is much smaller, often 0.5 to 2 grams of powder a day in divided doses. Because of the very high tannin content, internal use is best avoided unless a qualified practitioner is guiding you.
• Best time of day: For mouth and gum rinses, after brushing, two or three times a day. For sitz baths and skin compresses, whenever the area feels sore, often in the evening.
• With or without food: Do not swallow rinses or gargles. If a practitioner has advised a small internal dose, take it with food to reduce stomach irritation, and keep it at least two hours away from any medicine or iron supplement.
• Time to effect: The tightening, drying feeling of a rinse or wash is immediate. Any real change in a sore gum or weeping skin patch would take a few days. If nothing has changed in a week, it is not going to.
• How long to take it: Keep any use short. External rinses and washes are usually used for a few days up to about one week. Internal use should not run past two or three days without medical advice, because concentrated tannins can irritate the stomach and, in large or prolonged amounts, have been linked to liver injury. If the problem has not clearly improved within a week, stop and get it looked at.