Lady's bedstraw has a long history of use as a herbal medicine, though it is little used in modern medicine. Its main application is as a diuretic and as a treatment for skin complaints. The leaves, stems and flowering shoots are antispasmodic, astringent, diuretic, foot care, lithontripic and vulnerary. The plant is used as a remedy in gravel, stone or urinary disorders and is believed to be a remedy for epilepsy. A powder made from the fresh plant is used to soothe reddened skin and reduce inflammation whilst the plant is also used as a poultice on cuts, skin infections, slow-healing wounds etc. The plant is harvested as it comes into flower and is dried for later use. Both Asperuloside (a terpenoid) and Coumarin (a benzopyrone) occur in some species of Galium. Asperuloside can be converted into prostaglandins (hormone-like compounds that stimulate the uterus and affect blood vessels), making the genus of great interest to the pharmaceutical industry. Source: https://pfaf.org/
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