Laver, is an algae plant that grows on shallow sea rocks. The appearance color of fresh laver is slightly different due to the different components of chlorophyll, lutein, carotene, phycoerythrin, phycogreen protein, etc., thus showing red purple, green purple, black purple, brown green, etc. After drying, it is mainly purple. The ancient Chinese cooked it for food, so it was called laver, alias black cabbage, laver, purple cabbage, and according to its appearance and taste, there are names such as long laver, round laver, wrinkled laver and sweet laver.

In the 3rd century AD, the Western Jin Dynasty writer Zuo Si (about 250-about 305) wrote in Wu Du Fu that laver was born in the mountains along the sea in Wu Du. In the 5th century, during the Southern and Northern Dynasties, medical scientist Tao Hongjing (456- 536) recorded in the Notes to the Collection of Materia Medica that eating laver can "cure gall tumors and qi". In the Eastern Han Dynasty in the 2nd century, philologist Xu Shen (about 58-about 147) wrote in Shuowen Jiezi: "Gall, neck tumor." The most common is what was later called goiter, mostly caused by iodine deficiency. In the 7th century, Meng Xian of the Tang Dynasty said in Diet Therapy Materia Medica that laver "is green in the South China Sea, with stones attached, and purple when taken and dried". In the Song Dynasty, laver was used as a tribute.

Chinese people eat laver in various forms: chewing laver alone, cooking laver soup, rolling laver rolls, cooking soup with other foods, cooking with other foods, etc.

According to modern scientific knowledge, the composition of laver is not completely consistent due to different varieties. But no matter what species, are rich in iodine, is one of the ideal food to supplement the human body iodine. Porphyra taurine can promote lipase activity, reduce the body's bad cholesterol, inhibit nerve spasm, reduce anxiety, and has a protective effect on the liver. Porphyra contains eicosapentaenoic acid (Eicosapentaenoic Acid, referred to as EPA) and docosahexaenoic acid (Docosa-hexaenoic Acid, referred to as DHA), which can reduce blood lipids, regulate blood viscosity, reduce thrombosis, enhance brain function, delay aging, resist inflammation and prevent cancer. Porphyra contains cholinergic delay memory decline; contains mannitol has a diuretic effect, can be used as an adjuvant treatment for patients with edema. The dietary fiber of laver can help defecate and reduce the occurrence of constipation and rectal cancer. In addition, laver also contains a variety of amino acids, vitamins (A, B1, B2, B12, E, PP), minerals (potassium, calcium, phosphorus, iron, sodium, magnesium, manganese, selenium), etc., which are useful for maintaining bones, teeth and other organ functions, as well as treating anemia.

In short, Laver has a wide range of physiological and pharmacological effects, including regulating human sugar and fat metabolism, slowing coronary and cerebral arteriosclerosis, improving vision, and inhibiting gallstone formation. Eating seaweed can obtain many health benefits, so it is given the reputation of "longevity dish.

In order to avoid as much as possible calcium and tannic acid or oxalic acid into insoluble compounds on the human body, seaweed should not be with tannic acid or oxalic acid content of more food with cooking. Traditional Chinese medicine believes that people with spleen and stomach deficiency, abdominal pain, and loose stools should eat less or not eat laver temporarily.