Cambogia. Gamboge. The gum resin from undetermined species of Garcinia, imported from Siam. The Ceylon variety is derived from Hebradendron gambogioides. [Gambogia. Gamboge. The concrete juice of an undetermined tree. U. S.]

Description. The Siam gamboge occurs in pipes or cylinders,. externally streaked, from the impression of the bamboo reeds, in which the juice is collected; the pipes are from 1/2 inch to 1 1/2 inch or more in diameter. Gamboge is hard, brittle, breaking with a vitreous fracture, of a bright yellow colour: inferior varieties, in fragments and masses, also come from Siam; and a coarse kind is made at Ceylon.

Prop. & Comp. No odour, taste slight at first, afterwards acrid, easily powdered. It consists of about 70 per cent. of resin, gambogic acid (C40 H23 O8), with gum, etc.; when good, there is no starch; rubbed with water, the gum dissolves, the remainder is the suspended resin, forming a yellow emulsion. The resin dissolves in alcohol, but is again precipitated by water.

Off. Prep. Pilula Cambogiae Composita. Compound Gamboge Pill. [Not officinal in U. S. P.] (Gamboge, one ounce; Bar-badoes aloes, one ounce; aromatic powder, one ounce; hard soap, in powder, two ounces; syrup, a sufficiency.)

Therapeutics. Gamboge acts as a drastic and hydragogue purgative, often causing vomiting. It is seldom given alone, but combined with cream of tartar or calomel, it may be used in dropsies; and with aloes and aromatics, as an ordinary brisk purgative; sometimes as a vermifuge.

Dose. Of the powder, 1 gr. to 5 gr.; of pil. gambogiae c, 5 gr. to 15 gr.

Adulterations. An emulsion made with boiling water does not become green on the addition of iodine, showing the absence of starch, with which it is sometimes adulterated.