The Water Lilly has a long history of traditional medicinal use and modern research has shown the presence of several medically active compounds in the plant.
The alkaloid nymphaeum is found in all parts of the plant, other than the seed, whilst coclaurine has been found in the leaves and stem.
The plant contains several flavonoids such as kaempferols, quercetins and myricetins – these are found especially in the flowers.
The plant also contains a glycoside, nymphalid, which has a digitalis-like action upon the heart.
Alcoholic extracts of the rhizome, containing the alkaloid nymphaeum, have a mild sedative and spasmolytic action. They do not significantly depress the heart; in large doses though, they have a paralysing effect on the medulla.
The rhizomes are astringent, demulcent, diuretic, emollient and tonic.
A decoction is given in the treatment of diarrhoea, dysentery, stomach-ache, colic and dyspepsia.
An infusion of the fresh rhizomes is used for treating blennorrhagia and infections of the urinary tract.
The powdered rhizome is used as a demulcent for treating piles.
The slightly bitter juice of the leaves and petioles is used in the treatment of gonorrhoea.
The juice possesses mildly narcotic properties and is rubbed on the forehead and temples to produce sleep.
The juice from the leaves, or the macerated leaves, are an ingredient of a lotion applied to the skin for fever.The flowers are taken as a cardiotonic because of their astringent properties.