It is a herbaceous perennial, often cultivated as an annual, which forms a subshrub with an erect and very branched habit, up to 1 m high. The stems are quadrangular and hairy with opposite green or purple leaves, oval or elliptic-oval in shape, up to 4 cm long, with petioles of the same length as the blade and entire or slightly crenulate margins. The inflorescences arise in terminal racemes with bilabiate white, pink or lavender flowers. The essential oil contained in the plant gives it its characteristic aroma.