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.

The flowers are small, with a five-lobed white corolla, and produced several together in a corymb 3–5 cm diameter.

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

[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.