One of a genus of plants of the Natural Order of Polygonacea, Linnean system—Hexandria trigynia—the largest of all the Docks, it is a native of Europe, also of America. It grows from five to seven feet high; the stalks are round, thick, and striated, very upright, branched, and hollow; the leaves are very large, being from 18 inches to nearly a yard in length, of a pale green colour, but when exposed to the sun they sometimes turn to a brown or reddish brown colour; also they are very broad and sharp pointed, turning or leaning over a little at the point towards the water, in which they are found growing. The flowers are small, and of a greenish-yellow colour, with some white threads, which afterwards become brown. The root is very large, long, round, and of a reddish-brown colour; but if the roots are young they will be a bright yellow colour inside. It is a perennial plant, and flowers in July and August; grows in pits, ponds, ditches, by river sides, in canals, and is sometimes found in bogs or swampy places. The principles of the Great Water Dock Root are four in number: Resin, resinoid, alkaloid, and neutral. The extractive principles are: Iron, tannin, nitrate of soda, potash, phosphorus, sulphur, and oxalic acid. The properties of the extractive principles are: Astringent, tonic, nervine, diuretic, diaphoretic, anti-scorbutic, and laxative. The indications for their employment in disease are as follows:—Asiatic cholera, cholera-morbus, diarrhoea, weakness of the bowels, constipation, dysentery, dyspepsia, gravel, and stony formations, Bright's disease, torpid or sluggish liver, yellow jaundice, brain and nervous affections, nervous debility, fits, palpitation, scurvy, scrofulous affections, skin diseases, old wounds, seres, boils, and all impurities of the blood.
As an alterative, the Great Water Dock is deservedly held in high repute, and may be extensively employed. It proves most efficient, however, in scrofula, syphilis, and diseases of the skin; it operates kindly and without excitement, being slow but sure in promoting a healthy action of the depurative functions of the system. Its laxative properties are not displayed, except when given in large doses, and not even then if a considerable degree of hepatic torpor (sluggish liver) exists. It will be necessary, therefore, to use in such cases suitable mild laxatives in connection with the preparation of the Great Water Dock. When used to an extent sufficient to affect the bowels sensibly it reacts as a mild astringent, hence it is frequently employed in those cases where a mild astringent is indicated, as in the asthenic forms of diarrhoea and dysentery, and in the diarrhoea of phthisis or consumption.
The average dose of the decoction of the Root is about 2 ozs., to be given three, four, or five times a day, or subject to such variations as the circumstances of the case may require.
In cholera morbus its neutralising properties destroy the excess of acid in the stomach and bowels, and with the tannin quiets the irritation, and allays the sickness and vomiting; while the iron tones up and strengthens the muscles and walls of the stomach and bowels. The diarrhoea ceases in consequence; and the patient is in a state of convalescence. It has the same effect in dysentery (red or white) and simple diarrhoea.
In all cases of nervousness, nervous debility, fits, and palpitation it will be found an excellent remedy, as on account of the phosphorus it contains it forms a food for the brain and nervous system, and thereby strengthens and equalises the nerve current and allays irritation. The predisposing causes being overcome, the above-mentioned affections cease.
In dropsy, retention of urine, stone and gravel in the kidneys, bladder, and ureters, in Bright's disease, and in cases of gallstone, sluggish and torpid liver, the properties of Great Water Dock are highly useful, and will be found an excellent remedy. The Potash and Nitrate of Soda in these cases are beneficial, as by their solvent and diuretic properties stony and gravelly deposits are dissolved and expelled from the organs affected by them, and the urine or bile retained by them is liberated, and in case the structure of the organs affected has been ruptured or excoriated by the passage of stone or gravel, the tannin and iron, with their healing, strengthening and astringent properties, gives strength to the affected parts and promotes speedy healing.
In impurities of the blood, the oxalic acid and the sulphur it contains are useful, and for this reason Great Water Dock is a remedy for scurvy, scrofula, and skin diseases, and will be found especially useful in the treatment of old wounds, boils, sores, etc.; also to relieve pain in burns and scalds, as it allays the severe pain known as the "fire," and cools and tones the affected parts. It may be taken internally, and also used externally as a lotion.
A gargle prepared from Great Water Dock is extremely useful in ulcerations of the tongue and mouth, also in relaxed and elongated uvula, sore throat, etc. The powdered root makes an excellent dentifrice, strengthening the gums, healing sores, and hardening them. The properties I have ascribed to Great Water Dock are positive and uniform, and may be relied upon to accomplish all I have claimed for it. Its value once known to the practitioner, he will consider his therapeutic repertory incomplete without it.
Common Plants and their Uses in Medicine was written by Richard Lawrence Hool, F.N.A.M.H., in 1922.