Drymus brunneus is a species of dirt-colored seed bug in the family Rhyparochromidae found in the Palearctic. In the West Palearctic it is lacking only in the far north of Northern and Eastern Europe. In the East, the species ranges to the Caucasus and Siberia. In the Alps it is found up to 1300 meters above sea level. Habitats include shady deciduous and coniferous forests, lowland forests and occasionally more open habitats such as bogs and wet meadows. They are also found on banks by standing and flowing waters. In winter, flooding their habitat seems to be no problem.