Abstract Abu Bakr Mohammad Ibn Zakaria al-Razi, one of the greatest Iranian scientists in the Middle Ages, discovered “alcohol” through the distillation process for the first time. In spite of this discovery, which had been done via Razi’s ancient Latin version, some of the European historians of sciences denied it and attributed it to the occidentals’ chemists. More importantly, Razi’s version could be an experimental method for preparing alcohol. This method, however, had wrongly attributed to the occidentals’ scientists because the European scientists had been influenced by Islamic philosophers, especially Razi. After presenting a short history of the fabrication of alcohol in the world, this paper aimed to discuss in detail Razi’s treatise in this regard. Also, it re-examined his experimental method in the laboratory to show that his description of the operation had actually made this discovery possible with the chemical instruments of his time. It is important to know that in addition to Razi, other Islamic chemists like Jabir Ibn Hayyan, al-Kindi, and al-Antaki had already discovered alcohol through different methods. For example, in his book entitled "Kitāb Kīmiyā' al-'Iṭr Wat-Taṣ'īdāt", al-Kindi had discovered alcohol via wine distillation. However, Razi’s method was better than al-Kindi’s since the occidental alchemists of the Middle Ages had been more influenced by his method. Indeed, Razi was the first alchemist who discovered alcohol. Introduction In their books, some historians of chemistry have written that the production of alcohol from wine happened in the early 13th century. Their claim is based on a series of Latin instructions for producing "incendiary water" or "alcohol" from wine distillation. Nevertheless, all of these protocols have been included in Islamic alchemy. Although some prejudiced historians, such as Berthelot (Marcelin Berthelot, 1827-1907) and Ruska (Julius Ruska, 1867-1949), have denied this statement (Ruska, 1913: 322) (Berthelot, 1893: 336-50), the Latin version of Razi’s text for the preparation of alcohol is a strong confirmation of this claim. In fact, in the 19th century, Höfer, a French chemist, and Berthelot’s contemporary ones (Ferdinand Höfer, 1811-1878) discovered a Latin text from Muhammad Ibn Zakaria al-Razi, in which he had explicitly obtained alcohol from the distillation of starchy substances (Hoefer, 1866: 342). It should be noted that there are some Latin translations of Razi’s alchemical treatises, but unfortunately, their original Arabic texts have not yet been found. One of these translations is Razi’s famous treatise, which describes the preparation of alcohol. It may be a chapter of a book that has been missing since the Middle Ages. Indeed, the reasons for attributing the discovery of alcohol by Zakaria Razi can be summarized as follows: Although the original Arabic text of Razi's treatise has not yet been found (like some of his other works), there is a Medieval Latin translation of it entitled"fectim Liber peragisterii", which is now kept in the National Library of Paris (No. 6514). Höfer, a chemist and historian of chemistry, has translated this manuscript into French and published it in his book entitled "Histoire de la chime"(Paris, 1866). Most chemists have documented this French translation for calling Razi "the discoverer of alcohol". In his famous work entitled "History of Industry" (published in 1873, 7 years after the publication of Hoover’s book in Paris), Maigne, a great French historian of science and technology, has once again mentioned Razi as the discoverer of alcohol (Maigne, 1873: 34). The simulation of Razi's protocol in the laboratory, which has been done based on the instructors provided at the University of Applied Science and Technology, has shown that Razi's protocol for producing alcohol is completely correct. Materials and Methods This research was performed based on the library method. Thus, the required sources in different languages were collected by using the libraries in Iran and European countries and then subjected to scientific analysis. So far, no article or book about the discovery of alcohol in the Islamic world or its discovery by Razi has been published in Persian; hence, this article could be considered as the first scientific research in this field. To prove the correctness of Razi's protocol for preparing alcohol, his protocol was simulated by the students and instructors of the chemistry laboratory of Amirabad University of Applied Sciences in 1394 AH (2015). Discussion of Results and Conclusions In the Islamic Middle Ages, Jabir Ibn Hayyan talked about one of the properties of alcohol, namely its flammability. Al-Kindi, another Islamic scientist, discovered alcohol through wine distillation. Razi, the most famous Iranian chemist and physician, used the same approach with starchy substances, which we knew through the Latin translation of his text. It was not possible to surely say which one of these two scientists were pioneering alcohol preparation. However, Razi's work was superior to al-kindi's work since it had been translated into Latin in the Middle Ages and he could be thus called the first discoverer of alcohol.