Iodine was discovered in the residue of burnt seaweed in 1812. ( Courtois). 1820 Coindet gave iodine (KI) as the active ingredient in seaweed to goiter patients. The goiters shrank. However, toxic effects occurred from excess iodine in some patients. It was shelved for goiters after that.The major complication was toxic iodine induced thyrotoxicosis. This is the first description of any form of thyrotoxicosis by Coindet. They knew it worked but did not know it was replacing a deficiency of iodine. Most of the 19 th century few accepted that a disease could be caused by a lack of something. Even though iodine was not accepted as the cause in 1830 it was used to treat goiter in Columbia South America, and in 1850 by Chatin in France. It was thought goiter was caused by something in the water-toxin,bacteria, or a parasite. The cause was not determined until early 20th century when small amounts of iodine given to school girls in Akron Ohio prevented goiters.
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