Preparation of ethereal oils (Al-Duhoun) by Ibn Al-Quff (13th century A.D.).

Ibn Al-Quff was born in Damascus. He learned medicine from Ibn Abi Usaibia. Ibn Al-Quff was excelled in medicine as well as in Surgery. He wrote several books, of which was "Al-Qumdah" (The Authority on Surgery). Another book was "Al-Shafi" (The Healer) on medicine. In the book "The Authority on Surgery", Ibn Al-Quff has devoted a special chapter, on the preparation of ethereal oils, which was commonly known as Al-Duhoun. He has described about 34 different oils together with their medical action.