Iceland moss (Cetraria islandica) is well known for being nutritious, specifically for being rich in minerals and fiber. What makes Iceland moss special is that it contains both mucilage and bitter substances, which is a rare combination in medicinal herbs. It’s considered particularly effective to treat many kinds of digestive problems as the mucilage heals and protects the mucous membrane of the stomach but the bitter substances strengthen and stimulate digestion. Iceland moss works well to treat bloating, constipation, acid reflux, gastritis, gastric ulcers, and peptic ulcers. The antibacterial effects of Iceland moss have been demonstrated, for example against Helicobacter pylori, a bacteria that causes gastritis and stomach cancer.