What is Goldthread?

Goldthread is a small woodland plant of northern North America. Its thin, bright yellow root gives the plant its name. The root was used as a bitter mouth rinse and a bitter tonic.

The old name "mouth root" points to its main use. Folk healers and Eclectic doctors used it for sore mouths, canker sores and sore gums. The taste is sharp and very bitter.

Here is the honest verdict on the evidence. There are no good human trials on goldthread for any use. Long traditional use is not proof that it works, and it is not proof that it is safe.

Goldthread grows slowly and is gathered from the wild. In parts of its range it is now scarce. Many supply concerns and most product labels give no measured strength.

How does Goldthread work?

No one has shown in people what goldthread does. The ideas below come from lab work and from a single compound, not from the whole root.

The root contains berberine, a yellow plant compound. In test tubes, berberine slows the growth of some bacteria and yeasts. Whether that happens in a human mouth has not been shown.

Berberine on its own has been tested in people, but as a measured supplement dose. Those trials show small drops in blood sugar and blood fats. You cannot read those results across to a goldthread tincture of unknown strength.

A second idea is simpler. Very bitter tastes may trigger saliva and stomach juices. This has been seen in small studies of bitters in general, not of goldthread.

What forms does Goldthread come in?

Goldthread is sold in a few simple forms.

Dried root, whole or cut, sold loose by the ounce.

Tincture, which is the root soaked in alcohol.

Glycerite, an alcohol-free liquid extract.

A tea or decoction made from the dried root.

Mouthwashes and gargles that list goldthread among other herbs.

Bitters blends meant to be taken before meals.

Capsules are uncommon. Most berberine capsules on shelves use other plants, such as Chinese goldthread, barberry or goldenseal. Read the plant name on the label, not just the word "berberine".

Where it comes from:

Goldthread has a long record in northeastern North America. Several Native nations, including Penobscot, Abenaki, Cree and Mi'kmaq peoples, used the root for sore mouths and throats. The root was often chewed fresh or steeped in water.

Settlers took up the same use and the same name. Nineteenth-century Eclectic doctors listed goldthread as a bitter tonic. They gave it for poor appetite, weak digestion and mouth ulcers.

One historic use is now treated as unsafe. The root was swabbed in babies' mouths for thrush. Berberine-containing plants are no longer considered suitable for newborns.

Goldthread also appeared in older US pharmacy books. It faded from use as cheaper plants and newer drugs took its place.

What does Goldthread help with?

• Canker sores and sore gums: This is the use the plant is named for. Healers held the root in the mouth or rinsed with a weak tea. The reported effect was a drying, numbing feel on the sore spot. No trial has tested goldthread for mouth sores. Most canker sores heal on their own in one to two weeks. Any rinse can seem to help over that time.
• Sore throat, as a gargle: Goldthread was gargled for a raw or scratchy throat. The tannins in the root make tissue feel tighter, which may explain the sensation. There is no human evidence for this use. A sore throat with fever, a rash, or trouble swallowing needs a doctor, not a gargle.
• Poor appetite and sluggish digestion: Eclectic doctors used goldthread as a simple bitter before meals. The thinking was that a bitter taste wakes up the gut. Bitter herbs in general have been looked at in small studies, with mixed results. Goldthread itself has not been tested this way in people.
• Minor skin and eye washes: Older books describe weak goldthread washes for sore eyes and skin. This use has not been studied and is not advised today. Home-made eye washes carry a real risk of infection. A painful or red eye should be seen by a doctor or optician.
• Infant thrush: Swabbing a baby's mouth with goldthread was once common. It should not be done now. Berberine can push bilirubin (a yellow waste pigment) out of its binding sites in the blood. In newborns this may raise the risk of brain damage from jaundice. Infant thrush is treated safely by a doctor.

What are the side effects of Goldthread?

• Very bitter taste, which many people cannot tolerate
• Nausea or stomach upset
• Diarrhoea or, less often, constipation
• Temporary yellow staining of the tongue, teeth or dentures
• Low blood sugar signs, such as shakiness or sweating, in people on diabetes drugs
• Skin rash from handling the root
• Headache

Good to know:

Most reported effects are mild and stop when use stops. Taste and stomach upset are the common ones.

The serious risks are not side effects in healthy adults. They are the risks to babies, to pregnancy and to people on certain medicines. Those are listed in the safety section and they matter more than the mild effects above.

How much Goldthread should you take?

• Recommended daily: There is no established dose for goldthread. No health authority has set one, and trials have not found one. Labels on goldthread tinctures usually give a drop count in water, taken a few times a day. Loose root labels may suggest a small amount simmered as a tea. These numbers come from tradition and from the maker, not from testing. Strength varies a lot between products. Two tinctures with the same label can hold very different amounts of berberine. That is a good reason to treat any label figure with care and to ask a pharmacist before you start.
• Best time of day: Timing does not matter much. Bitters were taken shortly before meals, which is the usual habit with any bitter herb. A gargle or rinse was used when the mouth or throat felt sore.
• With or without food: Bitters are usually taken just before food. Taken on an empty stomach, strong bitters can cause nausea in some people. With a mouth rinse, food timing is not important.
• Time to effect: A rinse feels bitter and drying right away. That feeling is not the same as healing. If you use it as a bitter, any change in appetite would show within days. It is also quite possible that goldthread does nothing for you at all.
• How long to take it: Traditional use was short. The root was used for a few days while a sore mouth or throat settled. No one has studied what long daily use does. Because of that, no safe long-term period can be named. Talk to a doctor before using it for weeks on end.