Bladderwrack (Fucus)

Published June 1, 1990.
List of German Commission E Monographs (Phytotherapy)


Name of Drug

Fucus, bladderwrack.

Composition of Drug

Bladderwrack consists of the dried thallus of Fucus vesiculosus L. [Fam. Fucaceae], of Ascophyllum nodosum Le Jolis [Fam. Fucaceae], or of both species, as well as preparations thereof.


Preparations of bladderwrack are used for diseases of the thyroid, obesity, overweight, arteriosclerosis and digestive disorders, as well as for "cleansing the blood."

The effectiveness for the claimed applications is not verified.


Preparations containing a maximum daily dosage of 150 µg of iodine:

None known.

Above the dosage of 150 µg of iodine per day, there is danger that hyperthyroidism may be induced or existing hyperthyroidism may be made worse. In rare cases allergic reactions involving serious overall reactions may occur.


Since the efficacy of a dosage below 150 µg iodine/day has not been substantiated for the conditions listed, therapeutic use of the herb cannot be advocated. In view of the risks, the therapeutic use of doses above 150 µg iodine/day cannot be justified on the grounds of lack of activity.