Carrageenan is a natural material that comes from the red seaweed plant found in the Atlantic Ocean. When carrageenan is extracted from red seaweed by boiling it or treating it with hot alkali, it forms a gel-like material that gives it firmness and makes it an effective thickener for food products. Not surprisingly, carrageenan has been embraced as a food additive by the food industry where it's commonly used to thicken and add texture and stability to foods and beverages that would otherwise be too thin and lack the proper mouth feel."
All it takes is a glance at a few food labels to see how common carrageenan is as a food additive. Some common products that may contain carrageenan are salad dressings