Seaweeds used in food and herbal medicine come from multicellular marine algae species that grow from the seabed as well as in many lakes and rivers. The term "seaweed" collectively refers to many varieties of plants that don't all share a common origin.
Seaweed is highly nutritious and is a good source of iodine and fiber. It is used in sushi rolls, soups, breads and beverages. Seaweed extracts such as agar and carrageenan are widely used in the food industry as binders and preservatives. In medicine, seaweed was used by the ancient Romans to treat wounds and burns because of its antimicrobial and anti-inflammatory properties. Today, seaweed is used in making wound dressings and dental molds, and researchers are exploring seaweed's potential for fighting cancer.