Ledum palustre), commonly known as marsh Labrador tea, northern Labrador tea, marsh rosemary[2] or wild rosemary, is a flowering plant in the subsection Ledum of the large genus Rhododendron in the family Ericaceae.

[citation needed] Among the plant's terpenes is ledol, a cyclic alcohol with deliriant effects, although poisonous in large doses.

[3][4] This species is not to be confused with the traditionally-used one Rhododendron groenlandicum, found throughout Northern North America.

[6] Marsh Labrador tea has traditionally been used as a gruit in brewing beer in the Middle Ages.

[7] Due to its strong fragrance, it has also formerly been used as a natural deterrent against clothes moths, also mosquitos and bugs in general, in Scandinavia and in Eastern Europe.