Sweet gale grows in cool temperate regions of Eurasia and North America, from Labrador to Alaska and south to Long Island, Michigan and Oregon. It is a shrub of lake shores, stream banks, bogs, fens and swamps, often dominating the shoreline. Its roots carry nitrogen-fixing nodules that let it thrive in nutrient-poor peat, and individual plants can change sex from one year to the next.
In northwestern Europe the leaves were a main ingredient of gruit, the herb mixture used to flavour beer from the Middle Ages to the 16th century, before hops replaced it. The foliage has long served as an insect repellent, and the plant has also been used for yellow dye, candle wax and as a seasoning. One of its Quebec French names, bois-sent-bon, means sweet-smelling wood.