Marsh cudweed is little used in modern herbalism, though it is occasionally taken for its astringent, antiseptic and anticatarrhal properties. The whole plant is anti-inflammatory, astringent, diaphoretic and diuretic. It may also have aphrodisiac and anti-depressant effects. It is used both internally and externally in the treatment of laryngitis, upper respiratory catarrh and tonsillitis, whilst in Russia it is used in the treatment of high blood pressure. The plant is harvested when it is in flower and is dried for later use.