Colocynth is the prepared fruit of Citrullus Colocynthis (Cucumis Colocynthis, Linn.), or bitter cucumber, an annual plant, with trailing stems, bearing considerable resemblance to the water-melon, growing wild in the islands of the Archipelago, and in various parts of Africa and Asia. The fruit, which is about as large as an orange, and yellow when ripe, is gathered in autumn, deprived of its cortical portion, and dried, before being sent to market.


The prepared fruit, as kept in the shops, is in globular balls, about two or three inches in diameter, extremely light, of a whitish colour, and composed of a soft, spongy, tough pulp, or medullary matter, and numerous seeds, which constitute about 75 per cent. of the whole weight. The spongy portion has a very feeble odour, and an intensely bitter, nauseous taste. The seeds also are bitter, but in a less degree; and, having comparatively little of the purgative property, should be rejected, when the colocynth is prepared for use. Both the bitterness and medical virtues of the pith are extracted by water and alcohol.

Active Principle. Colocynth owes its virtues to a peculiar, neuter, bitter principle, called colocynthin, which is intensely bitter, soluble in alcohol, less soluble in water, and precipitated from its aqueous solution by infusion of galls. This principle is not isolated for medical use. There are also in the pulp considerable quantities of pectic acid and mucilaginous matter, which cause the decoction or hot infusion to gelatinize on cooling.

Medical Effects and Uses

Colocynth is a powerful, drastic, hydra-gogue purgative, occasionally, even in ordinary doses, operating harshly, and capable, in over-doses, of producing violent irritation of the stomach and bowels, with severe griping pains, bloody stools, etc. it has in several instances caused death, through inflammation of the alimentary canal; and in one instance, mentioned by Dr. Christison, this result took place from a teaspoonful and a half of the medicine. The irritation and inflammation have extended also to the kidneys, bladder, and genitals, showing that the bitter principle is probably absorbed, and operates through the circulation. Colocynth is said sometimes to act as a diuretic, and, if given so that its bitter principle might be absorbed without purging, it would be very likely to produce this effect. It is thought also to act on the liver, and by some to have a peculiar disposition to operate on the lower bowels, and, I have little doubt, is tonic in minute doses. it seems, indeed, to bear some resemblance to aloes, in its mode of action, though much more hydragogue, and more powerful.

It is very seldom administered alone, but almost always in connection with other cathartics, to which it gives increased activity, while its own violence is mitigated. in this mode, it is employed, in the full dose, whenever an energetic cathartic effect is demanded, and in small doses, as a laxative, in torpid conditions of the liver, and of the stomach and bowels generally. it is wholly unfit for cases in which the stomach or bowels are inflamed.

The dose of colocynth is from five to ten grains. When administered in pill or powder, the pulp should be thoroughly rubbed with gummy or starchy matter, so as to pulverize it well, and obtund its acrimony by separating its particles; and a little sulphate of potassa would be a good addition, with a view to a more thorough division and incorporation of the materials. The decoction and tincture, though active, are little employed, and not officinal in the United States or Great Britain. The form in which colocynth is almost exclusively used, in this country, is that of extract; and the compound extract is among the most popular of the cathartics.

The simple extract, denominated officinally Alcoholic Extract of Colocynth (Extractum Colocynthidis Alcoholicum, U. S.), is prepared from the medullary part, deprived of the seeds, by completely exhausting it with diluted alcohol, then carefully evaporating the resulting tincture to dryness, and reducing the residue to powder. Diluted alcohol is a much better solvent for this purpose than boiling water formerly used, because it leaves behind the gummy matter and pectin, which are not only inert, but impair the character of the extract containing them. This preparation is used exclusively as an ingredient of the compound extract next considered.

Compound Extract of Colocynth (Extractum Colocynthidis Com-positum, U. S., Br.) is prepared, according to the directions of our present Pharmacopoeia, by simply mixing, in the form of fine powder, alcoholic extract of colocynth, Socotrine aloes, resin of scammony, cardamom, and soap. The U. S. Pharmacopoeia of 1850 prepared it, as the British now does, by exhausting colocynth with diluted alcohol, then adding to the tincture aloes, scammony, and soap, and lastly evaporating to the proper consistence, adding powdered cardamom near the end of the process. The preparation is thus seen to contain the virtues of colocynth, scammony, and aloes, with soap to give it due consistence, render the mass more soluble, and perhaps to qualify the drastic character of the more active ingredients, and an aromatic to obviate nausea and griping. it is much used in small doses, as a tonic aperient, in constipation with a torpid state of the bowels, inactive hepatic function, or dyspeptic condition of the stomach. in the full dose, it is a powerful, yet sufficiently mild purgative, adapted to all conditions in which a full and effectual operation upon the bowels is required, whether in reference simply to the evacuation of the bowels themselves, or to a revulsive, or hydragogue effect. it is very frequently given in combination with calomel, in the complaints in which the latter cathartic is peculiarly indicated; and constitutes one of the ingredients of the Compound Cathartic Pills of our Pharmacopoeia, now so extensively used throughout the country. Hyoscyamus is often combined with it, in order to correct any griping tendency, and is an excellent addition. Such a combination was officinal with the Edinburgh College, under the name of Pilulae Colocynthidis et Hyoscyami, consisting of two parts of the extract and one of hyoscyamus, which might be given in about the same dose as the extract itself.

The dose of the compound extract of colocynth is from five to thirty grains. The medium full dose may be stated at fifteen grains, if the preparation be made from good materials. From three to five grains should operate as an aperient.

The Compound Pill of Colocynth (Pilula CoLocynthidis Composita), and the Pill of Colocynth and Hyoscyamus (Pilula Colocynthidis et Hyoscyami) of the British Pharmacopoeia, though containing essentially the same ingredients as the former-preparations, of the same name, of the British Colleges, are somewhat differently prepared; the former being made by mixing together powdered colocynth, Barbadoes aloes, scammony, and sulphate of potassa, with a little oil of cloves, and beating the whole into a mass with water; the latter, by the same process, except that extract of hyoscyamus is added at the same time as the oil of cloves. The sulphate of potassa is thought to favour the comminution of the other solid ingredients. The dose is from five to twenty grains.