Sefer Refuot

Sefer Refuot (, "The Book of Medicines"), also known as Sefer Asaph (, "The Book of Asaph"), is the earliest-known medical book written in Hebrew. Attributed or dedicated to Asaph the Physician (also known as Asaph ben Berechiah; possibly a Byzantine Jew; or possibly identifiable with Asif ibn Barkhiya, a legendary mystical polymath vizier in Arabic folklore, associated with King Solomon) and one Yoḥanan ben Zabda, who may have lived in Byzantine Palestine or Mesopotamia between the 3rd and 6th Centuries CE (though this is very uncertain, and some have suggested that Asaph and Yoḥanan were both legendary sages in Jewish tradition, to whom the text was dedicated; not its literal authors). The date of the text is uncertain, with most manuscripts coming from the late medieval era; though the lack of Arabian medical knowledge in the book implies it may have originally been written much earlier.
Content.
Sefer Refuot discusses illnesses, treatments and prevention. It shows great interest in general fitness and wellbeing through regimens of regular exercise, eating healthy food, and personal hygiene. The book shows concern for providing medicine for the poor and an interest in fostering medicine as a distinct profession. It gives a theory of blood vessels and circulation. The book also prescribes different remedies for each month of the year, based on the believed effects that astrology had upon the body's humors. The introduction to the book is in the form of the later Midrash, and ascribes the origin of medicine to Shem, who received it from angels.
The work notably includes the "Oath of Asaph", a code of conduct for Jewish physicians, strongly resembling the Hippocratic Oath. It was taken by medical students at their graduation.
Legacy.
The Israeli hospital Assaf HaRofeh is named after the author. Excerpts from the book appear in a modern Hebrew edition by Suessman Muntner.