The dose of rhubarb as a laxative is from three to ten grains. Five grains of good Russia rhubarb will generally operate decidedly in this way; and the best Chinese is but little inferior. For full purgative effect, the dose is from fifteen to thirty grains. More, however, is often required of the inferior powdered rhubarb, frequently found in the market. By roasting the root, its purgative effect is diminished, and the astringency relatively increased.

Rhubarb may be given either in powder, pill, infusion, tincture, wine, syrup, extract, or fluid extract. in whatever form administered, it may be advantageously combined with an aromatic, in order to correct its occasional griping effect. Under ordinary circumstances, when it is given as a laxative, the pilular form is most convenient.

A Compound Powder of Rhubarb (Pulvis Rhei Compositus, U. S., Br.) is directed in the U. S. and Br. Pharmacopoeias, consisting of rhubarb, magnesia, and ginger, of which the dose is from thirty grains to a drachm, or five to ten grains for a child. it is given in bowel complaints, when an antacid laxative is indicated.

The officinal Pills of Rhubarb (Pilula Rhei, U. S.) are made with rhubarb and a third of its weight of soap; and each pill contains three grains of the root. The soap is intended to render the pill more soluble. I have found, however, that rhubarb pills made simply with a little tincture of cardamom, while they have the advantage of the least possible bulk, operate well, and retain their power unabated for a long time. As a laxative, given at bedtime, the slowness of operation is no disadvantage. When it is desired that the medicine should act as quickly as possible, it should be given in another form.

The Compound Rhubarb Pills (Pilulae Rhei Compositae, U. 8., Br.) contain rhubarb, aloes, and myrrh, with a little oil of peppermint, and may be employed when a warming, tonic laxative is wanted, as in dyspepsia with costiveness, and there is no hemorrhoidal affection or tendency towards it. From one to four pills, or from five to twenty grains of the mass may be taken for a dose; the smallest quantity being used at first, when a simple laxative effect is wanted, and increased if necessary.

The officinal infusion of Rhubarb (infusum Rhei, U. S., Br.) is made by macerating two drachms of the bruised root, for two hours, in half a pint of boiling water. The dose is one or two fluidounces, which may be repeated at intervals of three or four hours till it operates. Advantage would often accrue from adding half a drachm of nutmeg or cardamom, or a drachm of fennel-seed to the rhubarb, in preparing the infusion, especially in cases of irritable stomach.

There are several officinal tinctures.

Tincture of Rhubarb (Tinctura Rhei, U. S., Br.) contains only rhubarb and cardamom, and may be used, in preference to the other forms, in low states of fever, as in typhus fever, for example, when a conjoint stimulant and laxative effect is wanted.

Tincture of Rhubarb and Aloes (Tinctura Rhei et Aloes, U. S. 1850, Ed.), sometimes called elixir sacrum or sacred elixir, differs from the simple tincture only in containing aloes, and may be preferred in the more inert states of the bowels, and especially when costiveness is conjoined with amenorrhoea. This is no longer officinal, having been rejected in the late revision of the U. S. Pharmacopoeia, and not adopted in the British.

Tincture of Rhubarb and Gentian (Tinctura Rhei et Gentians, U. S. 1850, Ed.) combines the virtues of a simple bitter with those of a laxative. it has ceased to be officinal, though well adapted to meet the joint indication for a tonic and laxative medicine.

Either of the above tinctures may be used, when a conjoint stomachic and laxative effect is desired, in cases permitting or requiring moderate stimulation. They are especially adapted to low states of the system, and to individuals who have been accustomed to the use of stimulant drinks. They are, however, chiefly employed as adjuvants to other preparations; being added to the solutions of the saline cathartics, tonic or laxative infusions, and various mixtures, when a warming or cordial impression on the stomach is desired. One may be selected in preference to another, according to the indications which may be offered. The dose as mere stomachic laxatives is from one to four fluidrachms, as purgatives from half a fluidounce to a fluidounce.

Tincture of Rhubarb and Senna (Tinctura Rhei et Sennae, U. S.) has been officinally adopted from popular usage. it is the preparation commonly known as Warners gout cordial, and contains, in addition to the cathartics mentioned in its title, other ingredients intended simply to give it colour, improve its taste, and render it more acceptable to the stomach. it is a feeble laxative, and may be given as such in chronic gouty cases, or others in which the susceptibility of the stomach has been impaired by indulgence in the use of alcoholic drinks. it is wholly unsuited to an unimpaired condition of the stomach; being much too stimulant in proportion to its purgative power. The dose is from half a fluidounce to two fluidounces.

There is an officinal Wine of Rhubarb (Vinum Rhei, U. S.), prepared from rhubarb and canella, which may be used as a cordial laxative in the dose of from one to four fluidrachms.

Two syrups are recognized by the U. S. Pharmacopoeia, the simple and aromatic.

Syrup of Rhubarb (Syrupus Rhei, U. S.) is prepared by mixing three fluidounces of the fluid extract with twenty-nine fluidounces of syrup. it is a mild cathartic, fitted especially for infants, to whom it is given in the dose of one or two fluidrachms.

Aromatic Syrup of Rhubarb (Syrupus Rhei Aromaticus, U. S.) differs from the preceding, in containing, besides rhubarb, some of the finer aromatics, namely, cloves, cinnamon, and nutmeg. it is an elegant preparation, admirably adapted to infantile diarrhoea, when there is no inflammation of the mucous membrane, or all acute symptoms have passed. it was much used popularly in this country, in the common summer complaint of children, under the name of spiced rhubarb, before being admitted into the Pharmacopoeia. The dose of it is a fluidrachm for an infant, repeated every two hours till it operates. The yellow-colour it imparts to the stools may be received as an evidence of its operation, in cases of diarrhoea. A little magnesia may often be combined with it advantageously.

Alcoholic Extract of Rhubarb (Extractum Rhei Alcoholicum, U. S.; Extractum Rhei, Br.) is prepared by first forming a tincture with diluted alcohol, and then evaporating by means of a water-bath. if properly prepared, it has the virtues of rhubarb in a concentrated state. The dose is from ten to twenty grains.

Fluid Extract of Rhubarb (Extractum Rhei Fluidum, U. S.) is a preparation peculiar to the U. S. Pharmacopoeia. it is made by first exhausting the root with diluted alcohol, then concentrating carefully, and adding sugar, which contributes to its preservation. The oils of anise and fennel, formerly added to the preparation, have been omitted in the present Pharmacopoeia. it is an elegant preparation, containing the virtues of rhubarb in a concentrated liquid form. The full dose of it, if well prepared from good rhubarb, should be half a fluidrachm for an adult, and from four to six minims for a child two years old; at all events, in reference to any particular parcel, it would be well not to exceed these doses until its activity has been tested by trial.

European Rhubarb. I have said little upon the subject of this variety of rhubarb, because its use should, I think, not be encouraged. it is less bitter and purgative, and relatively more astringent than the Asiatic rhubarb; and requires to be given in twice the dose, in order to produce the same effect. The consequences of introducing it into general use would be, to render the dose of rhubarb uncertain, and to lead almost inevitably to the adulteration of the finer kinds, for which I have understood that it is even now considerably used.