Iodine is an essential trace element for life, the heaviest element commonly needed by living organisms. In medicine, potassium iodide is usually used to treat acute thyrotoxicosis. Hyperthyroidism, an overactive thyroid, is a condition in which the thyroid gland produces and secretes excessive amounts of the free (not protein bound, and circulating in the blood) thyroid hormones, This is the opposite of hypothyroidism ('sluggish thyroid'), which is their reduced production and secretion. Graves' disease is the most common cause of hyperthyroidism. Iodine's main role in animal biology is as a constituent of the thyroid hormones thyroxine If there is a deficiency of dietary iodine, the thyroid will not be able to make thyroid hormone. The lack of thyroid hormone will lead to decreased negative feedback on the pituitary, leading to increased production of thyroid-stimulating hormone, which causes the thyroid to enlarge (the resulting medical condition is called endemic colloid goitre This has the effect of increasing the thyroid's ability to trap more iodide, compensating for the iodine deficiency and allowing it to produce adequate amounts of thyroid hormone. The thyroid hormones are essential to proper development and differentiation of all cells of the human body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. They also stimulate vitamin metabolism. Natural sources of iodine include sea life, such as kelp and certain seafood, as well as plants grown on iodine-rich soil. Iodized salt is fortified with iodine. Elemental iodine is used as a disinfectant in various forms. It is a wound cleaner and Iodine also acts as an expectorant of mucous from the common cold and other respiratory ailments. Iodine is a common aid for skin conditions, such as acne, ..A brown glass triangular shaped bottle with a plastic screw top lid that contained IodineFront Label : SANA / TINCTURE WEAK (2 1/2 % ) / IODINE / POISON / ANTISEPTIC COUNTER / IRRITANT ETC. / THE SANAX CO. / 5 BRUNSWICK STREET FITZROY / TEL. J 3208 MELBOURNE. on side : ANTIDOTE FOR IODINE / DIRECTIONS.........pharmacy, medicines, iodine, athritis, glassware, bottles, moorabbin, bentleigh, cheltenham, thyroxin, goitre, iodised salt, gravves' disease