The modern medical and pharmacological literature which deals with the therapeutic properties of hemp (Cannabis sativa L., Cannabaceae) tends to ignore the valuable contributions of Arabic scientists on the subject. The tradition of the plant’s medicinal use was adopted by these scientists from the cultures of the ancient world, having been used for more than a thousand years as a textile and medicine in Arabia, Mesopotamia, Persia, Egypt, China, India and extensive areas of Europe (Levey 1979; Escohotado 1989-1990). The role played by the medical, pharmacological and botanical literature of the Greeks in this regard is well-known, dominating medical circles in Asia Minor, Syria, Egypt and their neighbouring regions up until the arrival of Islam in the seventh century. The Materia medica of Dioscorides (AD first century), translated into Arabic by Istifn b. Bsl in the days of the caliph al-Mutawakkil (d. AD 861), and the De Simplicium Medicamentorum Temperamentis ac Facultatibus Liber VII of Galen (d. AD 199) similarly translated by Hunayn b. Ishq (d. AD 873), were by far the most important sources for Arabic physicians, and were a decisive stimulus in the development of their knowledge of the plant.