antiseptic introduced into medicine in 1829 by the French physician Jean Lugol. An effective bactericide and fungicide, Lugol's solution is a transparent brown liquid prepared by dissolving, first, 10 parts of potassium iodide, then 5 parts of iodine, in 85 parts of water. It is less irritating than iodine tincture (a solution in alcohol) when applied to open wounds.