The American Rat Root has been used mainly to ease digestive disorders, especially relieving flatulence and stomach cramps. It is also thought to be an effective expectorant that clears nasal and respiratory passages, and some herbal practitioners claim it even clears the mind.

History:
Rat Root is a vigorous, reed-like, aquatic plant with somewhat vague origins. Some say that it is a native of Europe; others claim Asia, and it is distributed widely in the temperate regions of the United States, Europe, Eurasia, and northern Asia Minor and throughout the Far East (including India, Indonesia and Sri Lanka).
This perennial plant bears sword-shaped leaves with small yellow and green flowers on a fleshy, cane-like stalk and thrives in rich, wet soil (or shallow water) in a sunny position, reaching a height of five feet.

Although the iris-like plant resembles "Yellow Flag" (a member of the lily family and the reason Rat Root is sometime called Sweet Flag), it is actually a member of the palm family and flourishes in ditches, lakesides and marshy places. The derivation of Rat Root's botanical name, Acorus, is also vague: Some say it is derived from the Greek word, coreon, meaning "pupil of the eye," referring to the plant's use to cure eye diseases; others say it is derived from an old Latin word meaning "aromatic plant," referring to the pleasant fragrance emitted from the reeds.

One of the herb's common names and botanical specific, calamus, is a translation of the Greek word meaning "reed," and its use in herbal medicine may be traced back to the ancients. Dioscorides prescribed it for Eye Problems, and in ancient India, practitioners employed it as a candied chewing medicine for coughs and bronchitis. In Europe and England, Rat Root was utilized as a popular "strewing herb" to ward off disease and to add a pleasant fragrance to churches; and the esteemed seventeenth-century English herbalist, Nicholas Culpepper, recommended Rat Root as a "strengthener of the stomach and head." Native Americans had so many medicinal uses for Rat Root that it was actually considered a commodity and medium of exchange.

Plains Indians chewed it for toothache, and the Meskwakis applied the boiled root to treat burns. Some of the Native Americans utilized the herb to increase strength and endurance, while other, more northerly tribes used it to help improve digestion and mental sharpness (echoing Culpepper's earlier recommendations), and the herb was included in the United States

Pharmacopoeia from 1820 through 1916 and the National Formulary from 1936 through 1950. The sweet-scented roots and leaves are used in perfumes, and its pungent, cinnamon-spicy qualities add flavor to candies, medicines, beers and gins, while the same aromatic, bitter roots and leaves are used in herbal medicines. Some of the constituents included in Rat Root are essential oil, choline, soft resin, gum, starch and the bitter glucoside, acorin.

Conditions:
Rat Root is an aromatic stimulant that has been used for centuries in many cultures mainly for digestive complaints. It is considered a "stomachic," or substance that stimulates and strengthens stomach function, and is said to benefit digestion, increase the appetite, ease dyspepsia and stomach cramps. The herb is thought to relieve the discomfort of flatulence, as well as check the growth of the Bacteria which gives rise to it.

As an expectorant, Rat Root has been used to loosen and expel phlegm from the respiratory tract and is said to be useful in cases of bronchitis and sinusitis. The powdered root was included in snuff to relieve nasal congestion and shock, and in European countries the root was included in lozenges to clear the voice and ease coughs.

Rat Root is considered a parasiticide that has been used to destroy and expel Parasites from the intestines (an insecticide is also produced from the essential oil).
As an emmenagogue, Rat Root has been used to stimulate and regulate menstrual flow.

Powdered Rat Root was once smoked or chewed, because it was thought to destroy the taste for tobacco and thus discourage and break the smoking habit.
Rat Root has been used to calm the nerves and act as a mild tonic that restores and nourishes the entire body by exerting a gentle strengthening effect. It was a very important herb in Ayurvedic medicine and was used as a restorative for the brain and nervous system, especially after a Stroke.
Used externally, Rat Root has been used to relieve burns, skin problems, eruptions, rheumatic pains and neuralgia.