Colocynth, the fruit of citrullus colocyn-this, a plant of the order cucurMtacece, somewhat resembling a small watermelon, and growing in various parts of Asia and Africa. The pulp of the fruit, deprived of rind and seeds, is intensely bitter and powerfully cathartic. These properties are due to colo-cynthine, a neutral bitter substance existing in the dried pulp in the proportion of about 14 per cent. Colocynth is used in medicine chiefly in the form of compound extract, in which it is combined with aloes, scammony, cardamom, and soap. This combination renders its action milder, but not less efficacious. It is still further combined with calomel, jalap, and gamboge, in the compound cathartic pill. A tincture is used in Germany. The unripe fruit is said to be eatable when pickled. A hybrid between the colocynth and the watermelon has been produced in this country, which possesses the bitterness and purgative properties of the former.