Laminaria japonica is an edible brown alga extensively cultivated and consumed in Korea, Japan, and China. It is native to Japan and is one of the most commonly consumed marine vegetables in Asian countries, especially Korea and Japan. L. japonica has been an important ingredient in making soup stock and traditional medicine for a long time.

It is considered a nutritious food and a good source of minerals, especially iodine. It is also rich in dietary fibers and polysaccharides. Several polysaccharides isolated from L. japonica, such as alginate, fucoidan, and laminaran, show diverse biological activities such as anti-oxidant, anti-coagulant, or anti-inflammatory properties. It was also reported that the extracts of L. japonica have anti-bacterial activities against oral microorganisms, not only against Escherichia coli and Staphylococcus aureus. It is high in alginic acid, dietary fiber, iodine, and calcium. A recent study demonstrated the skin moisturizing effect of L. japonica extract by decreasing TEWL value.