Sargassum Seaweed

Sargassum seaweed is a type of seaweed found along the coasts of Japan and China. Two species, Sargassum fusiforme and Sargassum pallidum, are both referred to as sargassum seaweed or gulfweed in English and hai zao in Chinese.

Sargassum seaweed is a brown algae with leafy segments supported at the surface of the ocean by air bladders. Many species of sargassum are found worldwide. In fact, the Sargasso Sea, an area of the Caribbean near the West Indies, is named for its large floating masses of sargassum seaweed. However, sargassum used in healing is usually of Asian origin.

General Use

Sargassum seaweed, or Hai zao, has been used in traditional Chinese medicine (TCM) since at least the eighth century A.D. In TCM it is characterized as having a cold nature and a salty, bitter taste.

The primary use of sargassum seaweed is to treat goiters. The thyroid needs iodine to produce a critical hormone, thyroxin, that regulates body metabolism. The primary natural sources of dietary iodine are sea salt, fish, and vegetables that live in the ocean.

Using sargassum seaweed as a source of iodine to treat goiters is a scientifically sound practice. In TCM, sargassum seaweed is also used to treat such other thyroid disorders as Hashimoto’s disease. It is also used to treat pain from hernia and swollen testes. Sargassum seaweed is found in many common Chinese formulas. In combination with silkworm, prunella, and scrophularia, it is used to treat scrofuloderma. When sargassum seaweed is combined with water chestnut, it is used to treat silicosis, a lung disease.

Sometimes modern herbalists use sargassum seaweed to promote weight loss because it encourages the body to discharge water through the urine. In China and Japan, fresh sargassum seaweed is sometimes stir-fried and eaten as a vegetable.

Sargassum also can be used for base material of alginat powder or natural fertilizer.