Jonathan Pereira FRS (22 May 1804, in London – 20 January 1853) was a pharmacologist, author of the Elements of Materia Medica, a standard work. He was examiner on the subject in the University of London. Life Pereira graduated as apothecary in 1823 after studying at the Aldersgate General Dispensary and St Bartholomew's Hospital. In 1826 he became lecturer on chemistry at the Royal College of Surgeons and in 1832 he was an established physician in London, being appointed professor of materia medica and lecturer in chemistry at the Aldersgate Medical School. In 1839 he became professor and lecturer at the London Hospital, where he received the position of assistant physician in 1841. Jonathan Pereira delivered the introductory lectures on Materia Medica in 1842 at the Pharmaceutical Society and one year later he was appointed as Professor of Materia Medica by this institution, examining the subject in the School of Pharmacy of the University of London. His subject area was the forerunner of pharmacology and he published a series of research papers on plant drugs. Pereira later resigned in 1852, the result of a dispute between the Council of the Pharmaceutical Society following the illegal publications of his lecture material. After this incident another teacher in material medica was not appointed, instead Robert Bentley, who was professor of botany at the time, was asked to combine the lectures with his botany lectures. Pereira's Materia Medica His interest in the area of crude drugs began when he realised that little was known about those imported into Britain. After years of research he acquired an extensive knowledge of the history of origin, morphology and histology of crude drugs where he was later appointed professor of materia medica at the London Hospital. His book on Materia Medica was the first great English work on Pharmacology and he was foremost in putting the knowledge and use of drugs on a scientific footing. During one of his first lectures held at the School of Pharmacy he spoke about ‘material medica consisting of three parts: (1) pharmacognosy, pharmacology, pharmacopathia or the history of simple drugs; (2) pharmacy, and (3) pharmacodynamics. It was here that he referred to the study of crude drugs under the name pharmacognosy instead of materia medica in what appeared to be the first time in which it was used, when in fact it was introduced by Seydler in 1817. It took many