Jean-Francois Coindet. Portrait of Jean-Francois Coindet, Swiss physician (1774-1834). As a medical doctor in 1820, Coindet introduced the use of iodine for the treatment of goitre, an enlargement of the thyroid gland. Today iodine is a standard treatment of goitre in the form of iodine rich food or iodized salt if iodine deficiency is identified as the cause. As long ago as the 16th century the Chinese used sea plants (containing iodine) to treat goitre.