Costum is what the Romans called the powdered root of the aromatic kusth plant, and it was used in the preparation of unguents. Putchuk, or kusth, as it is now known, was called Eastern, or Persian costum by the Roman poets. It was Persian in a sense, being marketed at Barbaricum, the port at the mouth of the Indus which was a Parthian-ruled state in the first century AD. Andrew Dalby states in his book Empire of Pleasures:

Putchuk came from "the highlands," that is, from Kashmir, where the kusth plant (Saussurea lappa) now grows and is "still used for scenting shawl," says J. G. Frazer. With a "burning taste and exquisite odour" putchuk was an inexpensive aromatic in the Roman Empire, only 5½ denarii the pound, and was used in the cheaper medical prescriptions and magical formulae.