Badderwrack has proved most useful in the treatment of underactive thyroid glands and goitre. Through the regulation of thyroid function there is an improvement in all the associated symptoms. Where obesity is associated with thyroid trouble, this herb may be very helpful in reducing the excess weight. It has a reputation in helping the relief of rheumatism and rheumatoid arthritis, both used internally and as an external application upon inflamed joints. The New Holistic Herbal, by David Hoffmann Pg. 182