Potassium iodide (KI) is a chemical compound composed of potassium and iodine. It is typically found as white crystalline powder or colorless crystals and is highly soluble in water. Potassium iodide has several important applications, both in the industrial and medical fields.

One of the primary uses of potassium iodide is in the production of iodized salt. Iodized salt is a crucial source of dietary iodine, an essential element for thyroid function and overall human health. Potassium iodide is added to salt to prevent iodine deficiency disorders, which can lead to goiter and other health problems.

In the medical field, potassium iodide has an important role in radiation emergencies. It is used as a thyroid-blocking agent to protect against the absorption of radioactive iodine in the event of a nuclear accident or radiation exposure. By saturating the thyroid gland with non-radioactive iodine, potassium iodide helps reduce the risk of thyroid cancer caused by exposure to radioactive iodine isotopes.