Rhubarb is a tall perennial herb which has very stout stems and roots with large radical leaves. The dried rhizomes, that is, the underground stems producing roots and leaf shoots of the plant, constitute the drug. The rhizomes should be collected from six or seven year old plants just before the flowering season. The root barks should be retained.
Rhubarb is a native of south eastern Russia. It is one of the oldest recorded herbal drugs, being mentioned in a Chinese herbal remedy dated around 2700 B.C. Rhubarb was introduced in Europe in comparatively recent times. It reached Britain only in the 16th century. It is now cultivated to a limited extent in India and Central Africa.
An analysis of rhubarb stalks shows it to consist substantial amount of moisture, protein, fat, minerals, fibre and carbohydrates. Their mineral and vitamin contents are calcium, phosphorus, iron and vitamin C. Its calorific value is 26.
The rhizomes of rhubarb yield glucoside rhaponticin and chrysophanic acid. The chief constituents of the herb are antheoquinone derivatives. The roots contain rhein and emodin. Rhizomes also yield an essential oil containing eugenol, a terpene alcohol and a product believed to be methyl heptyl ketone.
The herb is pungent and bitter. It increases the secretion and discharge of urine.
Rhubarb is employed in allopathic medicine largely as a purgative. It also contains tannins and therefore, after purgation, . it creates an astringent effect which causes constipation. It is thus suitable only in mild cases of constipation and not in chronic ones.
Due to its astringent action, rhubarb can be taken with beneficial results in cases of diarrhoea caused by the presence of any irritating substances in the intestines.
Rhubarb is a valuable everyday remedy in ailments of children. It is a safe purgative and also reduces excessive acidity in the digestive tract of children. Sometimes children develop diarrhoea due to excessive consumption of milk which causes putrefaction and consequently increases the acidity in the stomach. Rhubarb expels the putrefied faecal matter simultaneously reduces the acidity. Despite its constipative after effect, the motion stops automatically after the bowels are cleaned. Its dose is one gram for infants upto 2 years old.
Rhubarb is one of the effective home remedies for poison ivy. Raw rhubarb rubbed over the area where it itches, gives relief. The treatment is repeated if itching persists.
Rhubarb is also useful in treating biliousness, lumbago, agitated mind, sore eyes, piles, chronic bronchitis, chronic lever, asthma and coryza, pains and bruises.
Precautions: Rhubarb contains a considrable amount of oxalic acid. Daily use can lead to the formation of stones either in the kidney or the bladder and distressing nervous symptoms.
I It should be avoided altogether by those who have a tendency to wounds, gout, rheumatism, epilepsy and other associated diseases with uric acid.
The succulent petioles or leafy stalks are used for pies and sauces.