Lugol's iodine, also known as aqueous iodine and strong iodine solution, is a solution of potassium iodide with iodine in water. It is a medication and disinfectant used for a number of purposes. Taken by mouth it is used to treat thyrotoxicosis until surgery can be carried out, protect the thyroid gland from radioactive iodine, and to treat iodine deficiency. When applied to the cervix it is used to help in screening for cervical cancer. As a disinfectant it may be applied to small wounds such as a needle stick injury. A small amount may also be used for emergency disinfection of drinking water.
Side effects may include allergic reactions, headache, vomiting, and conjunctivitis. Long term use may result in trouble sleeping and depression. It should not typically be used during pregnancy or breastfeeding. Lugol's iodine is a liquid made up of two parts potassium iodide for every one part elemental iodine in water.
Lugols iodine was first made in 1829 by the French physician Jean Lugol. It is on the World Health Organizations List of Essential Medicines. Lugols iodine is available as a generic medication and over the counter. Lugols solution is available in different strengths of iodine. Large volumes of concentrations more than 2.2% may be subject to regulation.