Sappan is a small evergreen thorny tree, 3 to 6 m tall. It prefers clay and limestone lands.
The heartwood contains a red dye and is used medicinally to relieve pain. It is also used as dye for textiles, for prints and in ink making.
Use of sappan wood in the Far East is probably ancient; archaeological remains (silk textiles from the Loulan site) attest its use in the 2nd century BC.
Red wood were imported into Europe from the Far East to the discovery of America.
The coloring matter contained in the wood are brazilin, present in all red woods and flavanoids which are not very much colored; the red dye, brasilein, is obtained after oxidation of brazilin.
This is a very sensitive dye to light; it is not easy to use and it fixes better on animal fibers than on plant fibers.