Colocynth (Gr. kolokynthis), a well-known medicine, much used as a purgative, is the dried and powdered pulp of the Colocynth Gourdl, Coloquintida, Bitter Apple, or Bitter Cucumber, a globose fruit about the size of an orange, of a uniform yellow colour, with a smooth, thin, solid rind. The plant which produces it, Cucumis (or Citrullus) Colocynthis, is nearly allied to the Cucumber (q.v.). It is found very widely distributed over the Old World, growing in immense quantities on the sand hillocks of Egypt and Nubia. It is also common in India, Portugal, Spain, and Japan. It has long been known for its purgative properties, and as early as the 11th century was in use in Britain. The main supplies of the drug are obtained from Mogador, Spain, and Syria. The fruit is gathered when it begins to turn yellow, peeled, and dried quickly either in a stove or in the sun. It is chiefly in the form of a dried extract that it is used in medicine. It owes its properties to a bitter principle called Colocynthine, which is more or less abundantly present in the fruits of many of the gourdl family. It is a curious fact, but to which there are many analogies, that the seeds of the colocynth plant, produced in the midst of its medicinal pulp, are perfectly bland, and they even form an important article of food in the north of Africa.—The name False Colocynth is sometimes given to the Orange Gourdl (Cucurbita aurantia), sometimes cultivated as an ornamental plant in our gardens, on account of its globose, deep-orange fruit. The pulp of the fruit possesses the properties of colocynth, but in a milder degree.
Colocynth is generally administered in the form of pills, in which the extract is associated with aloes, scammony, and in some cases with calomel or with extract of hyoscyamus. In small doses, the colocynth acts as a safe and useful purgative; and when accompanied by hyoscyamus, the latter prevents much of the pain and griping which are attendant on the use of colocynth by itself. In large doses, colocynth is a poison. Colocynth enters into the composition of some moth powders, and renders them very efficacious.