Secondary and tertiary sources of herbal medicine information in the American Botanical Council library and literature database were searched for basic information on herbs for thyroid disorders in the Western and Asian herbal medicine traditions. Both the TCM and Western modalities may employ the use of seaweed and sea products in thyroid formulas these must be used with extreme caution due to the varying and often unpredictable effects of iodine supplementation on thyroid function. Much of this data has been the subject of a recent systematic review.
Chinese medicine, on the other hand, has several herbs and herbal formulas earmarked for the resolution of thyroid disease and thyroid nodules, which may be interpreted (depending on symptoms) in the context of traditional Chinese medicine (TCM) as a disturbance of qi, a condition of excess or insufficient yin, or an accumulation of stagnant "phlegm" or "blood." These herbs have also largely been studied individually only in vitro and in animals, but some clinical trial data are available on TCM herbal formulas for treating hyperthyroidism. There are no herbs indicated in the Western tradition for resolving thyroid nodules per se, and herbs to treat thyroid cancer are not distinct from other herbs used in this tradition for cancer. Traditional Western herbal medicine lacks a body of herbs earmarked for thyroid health, but modern research on a few of these herbs reveals potential clinical applications toward hyperthyroidism in humans. Botanical medicines to treat thyroid disease are limited and have not been widely studied in humans. An important minority of thyroid nodules are malignant. Physical irregularities, often termed nodules, occurring on the thyroid are a distinct condition of the gland and may arise simultaneously with these diseases, or emerge idiopathically with no symptoms. Both of these most often result from autoimmune disorders. The most common thyroid disorders are the under- or over-functioning of the gland-hypothyroidism and hyperthyroidism, respectively. Diseases of the thyroid are varied and can take many forms, which may or may not produce clinical symptoms that alert patients to their existence.