Potassium iodide (Standard) is the standard substance of Potassium iodide, and it is applicable for quantitative analysis, quality control, and related research in biochemical experiments. Potassium iodide is used as the treatment of overactive thyroid and as protection of the thyroid gland from the influences of radiation from swallowed or inhaled radioactive iodine. It may be used after accidental exposure to radioactive iodine or before and after administration of medicine containing radioactive iodine.