COLOCYNTH, Coloquintida or Bitter Apple, Citrullus Colocynthis, a plant of the natural order Cucurbitaceae. The flowers are unisexual; the male blossoms have five stamens with sinuous anthers, the female have reniform stigmas, and an ovary with three large fleshy placentas. The fruit is round, and about the size of an orange; it has a thick yellowish rind, and a light, spongy and very bitter pulp, which yields the colocynth of druggists. The seeds, which number from 200 to 300, and are disposed in vertical rows on the three parietal placentas of the fruit, are flat and ovoid and dark-brown; they are used as food by some of the tribes of the Sahara, and a coarse oil is expressed from them. The pulp contains only about 3.5% of fixed oil, whilst the seeds contains about 15%. The foliage resembles that of the cucumber, and the root is perennial. The plant has a wide range, being found in Ceylon, India, Persia, Arabia, Syria, North Africa, the Grecian Archipelago, the Cape Verd Islands, and the south-east of Spain. The term pakkuoth, translated “wild gourds” in 2 Kings iv. 39, is thought to refer to the fruit of the colocynth; but, according to Dr Olaf Celsius (1670–1756), a Swedish theologian and naturalist, it signifies a plant known as the squirting cucumber, Ecbalium Elaterium.

The commercial colocynth consists of the peeled and dried fruits. In the preparation of the drug, the seeds are always removed from the pulp. Its active principle is an intensely bitter amorphous or crystalline glucoside, colocynthin, C56H84O23, soluble in water, ether and alcohol, and decomposable by acids into glucose and a resin, colocynthein, C40H54O13. Colocynthein also occurs as such in the drug, together with at least two other resins, citrullin and colocynthiden. Colocynthin has been used as a hypodermic purgative—a class of drugs practically nonexistent, and highly to be desired in numberless cases of apoplexy. The dose recommended for hypodermic injection is fifteen minims of a 1% solution in glycerin.

The British Pharmacopeia contains a compound extract of colocynth, which no one ever uses; a compound pill—dose 4 to 8 grains—in which oil of cloves is included in order to relieve the griping caused by the drug; and the Pilula Colocynthidis et Hyoscyami, which contains 2 parts of the compound pill to 1 of extract of hyoscyamus. This is by far the best preparation, the hyoscyamus being added to prevent the pain and griping which is attendant on the use of colocynth alone. The official dose of this pill is 4 to 8 grains, but the most effective and least disagreeable manner in which to obtain its action is to give four two-grain pills at intervals of an hour or so.

In minute doses colocynth acts simply as a bitter, but is never given for this purpose. In ordinary doses it greatly increases the secretion of the small intestine and stimulates its muscular coat. The gall-bladder is also stimulated, and the biliary function of the liver, so that colocynth is both an excretory and a secretory cholagogue. The action which follows hypodermic injection is due to the excretion of the drug from the blood into the alimentary canal. Though colocynth is a drastic hydragogue cathartic, it is desirable, as a rule, to supplement its action by some drug, such as aloes, which acts on the large intestine, and a sedative must always be added. Owing to its irritant properties, the drug must not be used habitually, but it is very valuable in initiating the treatment of simple chronic constipation, and its pharmacological properties obviously render it especially useful in cases of hepatitis and congestion of the liver.

Colocynth was known to the ancient Greek, Roman and Arabic physicians; and in an Anglo-Saxon herbal of the 11th century (Cockayne, Leechdoms, &c., vol. i. p. 325, London, 1864), the following directions are given as to its use:—“For stirring of the inwards, take the inward neshness of the fruit, without the kernels, by weight of two pennies; give it, pounded in lithe beer to be drunk, it stirreth the inwards.”