Lemon balm, also known as melissa officinalis, is a perennial herb in the mint family. Lemon balm has been used since the Middle Ages as a soothing herb that promotes sleep, reduces anxiety, helps manage stress and improves general health. The plan is native to Europe, it grows up to 2 feet tall and is easily distinguished by its small yellow flowers growing between the leaves and the stem. The leaves are extremely fragrant and produce a tangy, sweet aroma reminiscent of lemon when rubbed between the fingers.