Melilotus is a biennial herbaceous plant, sometimes more than 1 m (39 in) in height. It grows in the highland areas
of Europe and Asia. The plant exhibits a long, spindle-shaped root; a smooth, reddish, erect stalk; alternated leaves consisting of
three small, oval leaves; and small, yellow, highly scented flowers (May to September). The parts used are the dried flowering tops.
Melilotus has a sweet, aromatic odor and flavor.
The scent of melilotus is formed primarily during the drying process, during which coumarin is formed. Free couma rin is the main constituent of melilotus, together with melilotoside dihydrocoumarin.