What is Silverweed?

Silverweed is a low, creeping plant in the rose family. Its leaves are feathery, with a silky silver underside. Single yellow flowers sit on short stalks through the summer.

It grows across Norway, Sweden, Denmark and Iceland. You find it on damp ground, farm tracks and sandy shores. Folk names include gåsemure (Norwegian), gåsört (Swedish) and tágamura (Icelandic).

In Nordic folk use, the leaf was brewed as a tea for loose bowels and cramps. Today the dried leaf is sold as a tea herb and, less often, as a tincture.

Traditional use is not proof that a plant works, and it is not proof that it is safe. For silverweed, human evidence is close to absent. Read the rest of this page as folk practice plus laboratory hints, not as treatment.

How does Silverweed work?

The main idea behind silverweed is astringency: tannins that make tissue feel tight and dry.

In test tubes, plant tannins bind to proteins on the surface of tissue. That binding can draw the surface together and cut weeping slightly. This is the standard reason folk healers used tannin-rich teas for loose bowels and sore mouths.

Whether that happens in your gut, at the strength of a cup of tea, has not been tested in people.

Extracts of silverweed show antioxidant activity in laboratory assays. In some animal work, plant sugars from the species lowered blood glucose (blood sugar). Animal and dish results do not tell you what a tea does in a person.

The old name "cramp weed" came from a claimed muscle-relaxing effect. No good human study supports that claim.

What forms does Silverweed come in?

Most silverweed on sale is simply the dried leaf.

- Loose dried herb, brewed as a tea or infusion. - Tea bags, often in Nordic folk-herb blends. - Tincture, the herb soaked in alcohol.

- A cooled brew used as a mouth rinse or gargle. - A cooled brew used as a wash on intact skin. - Capsules, which are uncommon for this plant.

The root was eaten as a starchy food in hard years, not sold as a remedy. Products are rarely standardised, so strength differs between brands.

Where it comes from:

Silverweed had a long place in Nordic and wider North European folk practice.

Scandinavian healers brewed the leaf for loose bowels and stomach upset. The same brew was used as a gargle for sore throats and sore gums. Cooled, it was laid on grazes and small wounds.

It was also called cramp weed. Country users drank it for period pain and leg cramps.

The roots were dug and boiled as food in Iceland, the Faroes, Scotland and coastal Norway. In famine years they were a real calorie source. The Nordic names point to geese, which graze the plant heavily.

Older European herbals list the plant for the same handful of uses. That record shows what people did. It does not show that any of it worked.

What does Silverweed help with?

• Mild short-term diarrhoea: This is the best-known folk use. The tea was drunk to firm up loose stools. The idea is standard for tannin herbs, and tannins do bind tissue proteins in test tubes. No human trial has tested silverweed for diarrhoea. Diarrhoea with blood, fever, or lasting more than two days needs a doctor, not a tea. Fluids and salts matter far more than any herb.
• Sore mouth, sore gums and sore throat (as a gargle): Tradition used a cooled brew as a rinse, spat out rather than swallowed. Astringent rinses can feel tightening and briefly soothing. That is a sensation, not proof of healing. No human study has tested silverweed rinses. A sore throat with high fever, or trouble swallowing, needs medical review.
• Period cramps: The old name cramp weed came from this use. Women drank the tea for period pain and leg cramps. There is no human trial, and no clear laboratory finding that supports a muscle-relaxing effect. Treat this as folklore only. Severe or worsening period pain deserves a proper check with a doctor.
• Mild stomach upset: Bitter, astringent teas were a common household answer to an unsettled stomach. Any benefit here may be warmth, fluid and habit. Silverweed has not been tested for this in people. In some users tannins make nausea worse rather than better.
• Washing minor grazes: A cooled brew was used to wipe small, clean grazes. Some Potentilla extracts slow bacterial growth in laboratory dishes. Whether that happens on skin is not established. Deep, dirty, large or spreading wounds need proper cleaning and medical care, not a herb wash.

Which foods are rich in Silverweed?

Silverweed is not a nutrient, so no food is rich in it. The starchy root was boiled and eaten as famine food in Iceland, the Faroes and Scotland. That is a historical food use, not a health claim.

What are the side effects of Silverweed?

• Dry, puckering feeling in the mouth
• Nausea
• Stomach ache or cramping
• Constipation with heavy use
• Reduced iron absorption from food
• Allergic rash or itching (uncommon)

Good to know:

Reported problems are mild and mostly come from the tannins.

At tea strength, most adults who try it notice nothing beyond a dry mouth. Larger amounts and daily use raise the risk of nausea and constipation.

Because there is no safety trial, rare or delayed effects would not have been picked up. Stop if anything new or unpleasant starts, and get advice if it does not settle.

How much Silverweed should you take?

• Recommended daily: Silverweed is sold as a tea herb, and labels usually describe about 1 to 2 grams of dried leaf per cup, up to two or three cups a day. That figure is reported here as label practice. It is not advice for you, and it is not a tested dose. No trial has set a safe or useful amount in people. Products are not standardised, so two brands can differ widely in tannin strength.
• Best time of day: Time of day does not matter much for this plant. Spacing does matter. Keep silverweed tea about two hours away from iron tablets, thyroid tablets and other oral medicines. Tannins can bind drugs in the gut and cut how much you absorb.
• With or without food: A tannin tea sits better after food. On an empty stomach it can cause nausea or a dull stomach ache. If you use it at all, taking it with or after a meal is gentler. The trade-off is that tannins with a meal may reduce iron uptake from that meal.
• Time to effect: If an astringent tea is going to feel like anything, it is usually within hours. The drying, puckering feel in the mouth is immediate. That feel is not evidence of a gut effect. It may well do nothing at all. No human study has measured any effect, so there is no honest timeline to give.
• How long to take it: Folk use was short: a few days at most, for a passing problem. No one has studied long-term use, so no safe long-term period can be named. Steady daily use of a high-tannin tea may cut how much iron you absorb from food. If diarrhoea lasts more than two days, stop and see a doctor.