He became director of a hospital inBaghdad, and was personal physician to fourAbbasid caliphs. He composed medical treatises on several topics, includingophthalmology, fevers, leprosy, headache, melancholia, dietetics, the testing of physicians, and medicalaphorisms. One of Masawaiyh's treatises concerns aromatics, entitled,On Simple Aromatic Substances.
It was reported that Ibn Masawayh regularly held an assembly where he consulted with patients and discussed subjects with his pupils. Ibn Masawayh attracted considerable audiences, having acquired a reputation forrepartee.
Many anatomical and medical writings are credited to him, notably theDisorder of the Eye (Daghal al-ʿayn), which is the earliest systematic treatise on ophthalmology extant in Arabic, andThe Aphorisms, the Latin translation of which was very popular in theMiddle Ages.[7]
J.-C. Vadet, "Ibn Masawayh" in, The Encyclopaedia of Islam, 2nd edition, ed. by H.A.R. Gibbs, B. Lewis, Ch. Pellat, C. Bosworth et al., 11 vols. (Leiden: E.J. Brill, 1960-2002) vol. 3, pp. 872–873
Manfred Ullmann, Die Medizin im Islam, Handbuch der Orientalistik, Abteilung I, Ergänzungsband vi, Abschnitt 1 (Leiden: E.J. Brill, 1970), pp. 112–115
Fuat Sezgin, Medizin-Pharmazie-Zoologie-Tierheilkunde bis ca 430 H., Geschichte des arabischen Schrifttums, Band 3 (Leiden: E.J. Brill, 1970), pp. 231–236.
^V.C. Medvei,The History of Clinical Endocrinology, p. 45.
^Irwin, Robert, ed. (2010).The new Cambridge history of Islam, Volume 4 (1. publ. ed.). Cambridge: Cambridge University Press. p. 663.ISBN978-0-521-83824-5.
^Versteegh, Kees (2025). "Yūḥannā ibn Māsawayh". InAbdel Haleem, M. A. S.;Shah, Mustafa (eds.).The I. B. Tauris Biographical Dictionary of Islamic Civilization.
^abcdeSarton, George (1927).Introduction to the History of Science, Volume I. From Homer to Omar Khayyam. Baltimore: Carnegie Institution of Washington. p. 574.OCLC874972552.
