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DISCLAIMER: These pages are presented solely as a source of INFORMATION and ENTERTAINMENT and to provide stern warnings against use where appropriate. No claims are made for the efficacy of any herb nor for any historical herbal treatment. In no way can the information provided here take the place of the standard, legal, medical practice of any country. Additionally, some of these plants are extremely toxic and should be used only by licensed professionals who have the means to process them properly into appropriate pharmaceuticals. One final note: many plants were used for a wide range of illnesses in the past, but be aware that many of the historical uses have proven to be ineffective for the problems to which they were applied.

a.k.a. Black tang, Bladder fucus, Cutweed, Gulf wrack, Kelpware, Quercus marina, Rockweed, Sea oak, Seaweed, Seawrack, Wrack
(Fucus vesiculosus)

The actual iodine requirements in a healthy adult should not exceed 150 micrograms (a very small amount more than adequately supplied in normal daily use of iodized table salt).
Doses over 150µg of iodine per day can induce hyperthyroidism or make existing hyperthyroidism worse.
SYMPTOMS of excessive thyroid stimulation are thyroid enlargement, rapid heart beat, palpitations, nervousness, agitation, increased sweating, fatigue, muscle weakness, insomnia, and increased appetite with weight loss.
NOT used when pregnant or nursing.
NOT used when gastro-intestinal bleeding is present.
Rare cases of allergic reactions have been reported.
Should be avoided by those who must restrict their salt intake.

DRUG INTERACTION: Possible problem with lithium enhancing the hypothyroid action of large quantities of iodides.

CONTAINS: Mucilage, iodine, bromine, algin, carotenoids, xanthophyll, fucosterin, fucoxanthin, zeaxanthin, mannitol, volatile oil, pigments.

An important seaweed of the brown type used to make kelp tablets. Leathery and shiny olive-green to yellow-brown in color (blackish when dried), it grows in long ribbons (thalli) to about 3 feet in length and about 2 inches wide with an entire margin. On either side of the mid-rib are air-containing bladders which keep the plant floating upright from its anchorage on stones. Can be found growing in the coastal areas of the Atlantic and Pacific oceans.
"Fucus" is derived directly from the Latin and means 'brown seaweed'. "Vesiculosus" is also taken from the Latin 'vesicula' and means 'little blisters' in reference to the air bladders.
Although many health claims are made for the use of seaweeds, they can cause more harm than good unless prescribed by a medical professional. In the Oriental tradition they are generally used as a seasoning in soups, etc.

HARVEST: Not a cultivated crop. It is collected wild from unpolluted (especially that of heavy metals) coastlines in summer at low tides (plants washed up on shore are not suitable for internal consumption), then dried after a thorough washing; when brittle, the strips, or ribbons (also known as 'thalli') are cut up fine and ground.
PART USED: Whole plant.
TOOTHED WRACK (Fucus serratus): Used the same as F. vesiculosus.
Ascophyllum nodosum: Used similarly.


Alterative, antibiotic, anti-inflammatory, antirheumatic, diuretic, mucilaginous, salty, tonic, metabolic stimulant, nutritive, thyroid stimulant.
Has been used internally for treatment of goiter; has also been used to control obesity related to thyroid deficiency, but due to inherent dangers of overstimulating the thyroid, this is not recommended.
Has been used externally to treat rheumatic conditions as an oil, or added to bath water.
Has been used as a food supplement considered beneficial to skin and hair and as a bulk laxative which is gentle in action.
In Asian medicine it has been used in cases of fatigue and for convalescence.
Has a folk medicine history for treating arteriosclerosis, asthma, bronchitis, burns, colitis, constipation, digestive disorders, emphysema, gallstones, insect bites, obesity, scrofula, to combat stress, skin diseases, ulcers, problems associated with the genito-urinary and reproductive systems of both sexes, and as a "blood cleanser", although effectiveness for these claims has never been verified.

None can be safely recommended.
Information for researchers: The historical dose was 1 tsp daily for thyroid, 3 tsp daily as a laxative, 3 to 6 tablets or caplets daily as a metabolic stimulant and 1/2 to 1 fl. dram of the tincture; an infusion was made by steeping 1 heaping tsp in 1 cup boiling water for 30 minutes, then taken an hour before meals.
WRACK OIL = Steep 3.5 oz of dried bladderwrack overnight in 3.5 fluid oz. of sunflower or olive oil; in morning, heat in top of double boiler over low heat for 2 hours, then strain; oil has been used externally for arthritis or rheumatism pain.

Used as manure, soil conditioner, and is especially important as a high potash fertilizer for potatoes. It is spread fresh or dried directly onto the soil and dug in; small amounts are added to compost heaps where it acts as an activator.

Used as livestock feed.

Used to make mineral supplements (kelp tablets).
A source of alginates used in the food, cosmetic, and pharmaceutical industries.

©2004 by Ernestina Parziale, CH