Bladderwrack contains alginic acid, a kind of dietary fiber. Fiber helps with constipation, but it can also relieve diarrhea and keep your bowel movements more regular in general.
Bladderwrack is a demulcent herb, meaning it seems to work by decreasing inflammation and forming a barrier against irritants such as stomach acid.
Side Effects Bladderwrack is generally safe, though there are three potential problems with its consumption: acne, thyroid dysfunction, and heavy-metal contamination. Iodine in any form—including from bladderwrack and other seaweeds—can cause or aggravate acne in some people.