Botanical name

Fucus vesiculosus

Common Names

Kelp, black tang, bladder fucus, rockweed, sea oak, black tany, red fucus, dyers fucus, cut weed, rock wrack




A seaweed found on the coasts of the Baltic and North sea. 

Part supplied

The dried thallus. 

Food Use


Use 1 teaspoon of dried herb to one cup of boiling water to make a tasty tea. Infuse for 5-10 minutes. Sweeten with honey or lemon to taste.

Alternatively add half a teaspoon (2.5 ml) of tincture to a cup of warm water for a quick alternative to tea.

The herb can be added as a flavouring to gin, vodka and other infusions.

Medicinal Use

Key actions: Demulcent, thyroid stimulant, reduces weight. 

In clinic: Herbalists use this herb to treat rheumatoid arthritis, underactive thyroid, obesity.

If you are interested in the medicinal use of this herb please consult a herbalist. Herbs are generally used at medicinal strength, in blends, prescribed for each unique patient's condition.


Infusion: 2 to 3 teaspoons of herb to a cup of cold water. Pour boiling water over the herb and leave to infuse for 5 to 10 minutes. Flavour with lemon, ginger or honey if desired. Drink 3 times a day unless otherwise told by a medical herbalist.

Tincture: Take 1.3 to 3.3 ml (1:5 tincture), 3 times a day or as directed by a practitioner.

Fluid extract: 1:1 Take 1.5 to 2.8 ml, 3 times a day or as directed by a practitioner.

Dried Herb: Maximum of 2 g per day may be taken as a powder or capsules.

Other Uses

Cosmetic Use

None known.

Other Uses

None known.



Do not use if you suffer from hyperthyroidism, or have heart issues in association with this. 

This herb is considered safe in food amounts. Do not take if you are allergic to this plant or other members of this plant's family. Not all herbs are suitable in pregnancy, breastfeeding or for young children. If in doubt, please ask us or your medical herbalist.

Side effects

Plant extracts cause few side effects when taken correctly but if a side effect is experienced please contact us.

Interactions with drugs

Herbal remedies and supplements can interact with medicines. If you are taking medication please check with your medical practitioner, or call us, before taking herbs, supplements and medication together.

More Information


There are currently no articles related to this herb.


Look in our recipes section for more uses of this herb.


Read the latest PubMed research on this herb.

Add to BagBladderwrack Thallus Dried 1kg (Fucus versiculosus) £28.99
Add to BagBladderwrack Thallus Tincture 100ml (Fucus versiculosus) £7.00
Add to BagBladderwrack Thallus Essence 500ml (Fucus versiculosus) £16.00
Add to BagBladderwrack Thallus Essence 1 litre (Fucus vesiculosus) £31.00

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