This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Two kinds of zedoary are noticed by authors, the round and the long; but the former only is now to be found in the shops. The round zedoary is the root of Curcuma Zedoaria, growing in the East Indies, where it is cultivated. It is usually in slices, which are the halves or quarters of a roundish root, ending in a point. These are marked, on their convex surface, with the sections of circular rings, which in the whole root surround it horizontally, and with small projecting points, which are the remains of the radical fibres. The root is grayish-white on the outside, yellowish-brown and somewhat marbled on the freshly cut surface, hard, and compact. Its odour is agreeably aromatic, and its taste bitterish, pungent, and camphorous. Its activity resides mainly in a volatile oil; but the bitterness is probably dependent on a distinct principle, which may add a slight tonic influence to the aromatic qualities of the root. Its medical properties and effects are essentially the same as those of ginger, though weaker. It is at present seldom if ever used in this country. The dose is from ten to thirty grains.