Fucus vesiculosus  is a brown seaweed that grows on the northern coasts of the Atlantic and Pacific oceans, and the North and Baltic seas. Its name is sometimes used for  Ascophyllum nodosum,  which is another brown seaweed that grows alongside  Fucus vesiculosus . These species are often included in kelp preparations along with other types of seaweed.

The Vietnamese consume seaweed as food in various forms: raw as salad and vegetable, pickle with sauce or with vinegar, relish or sweetened jellies and also cooked for vegetable soup. As herbal medicine, seaweed is has been used for traditional cosmetics, treatments for cough, asthma, hemorrhoid, boils, goiters, stomach ailments, urinary diseases, reducing the incidence of tumors, ulcers and headaches. Although Vietnam has an abundance of algae floral with total number of species is estimated to be nearly 1,000 species of which there are 638 species of marine algae identified.

Black-tang, bladder, bladder fucus, bladderwrack, Blasen-tang, brown algae, common seawrack, cut weed, Dyers fucus, edible seaweed, fucoidan, fucoxantin, Fucus, green algae, Hai-ts'ao, kelp, kelpware, knotted wrack, Meereiche, Quercus marina, popping wrack, red algae, red fucus, rockrack, rockweed, schweintang, sea kelp, sea oak, seetang, seaware, seaweed, sea wrack, swine tang, tang, Varech vesiculeux, vraic, wrack.

*Key to grades

A: Strong scientific evidence for this use;

B: Good scientific evidence for this use;

C: Unclear scientific evidence for this use;

D: Fair scientific evidence against this use;

F: Strong scientific evidence against this use.

Grading rationale

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Adults (18 years and older)

Soft capsules (alcohol extract) in doses of 200 to 600 milligrams daily have been taken by mouth. Tablets have also been used, initially taken three times per day and gradually increased to 24 tablets per day. 16 grams of bruised plant mixed with one pint of water has been used, administered in 2 fluid ounce doses three times per day, or an alcoholic liquid extract in a dose of 4 to 8 milliliters before meals.

Topical (on the skin) bladderwrack and seaweed patches are sold commercially as weight loss products, although there are no commonly accepted or well tested doses.

Children (under 18 years old)

There is not enough scientific evidence to recommend safe use of bladderwrack in children. Because of the iodine content and potential for contamination with heavy metals, it may be inadvisable for use in children.