The Abbassid caliph Al-Mu'tasim (833–842) took him into the service of the court, which he continued under Al-Mutawakkil (847–861). Ali ibn Sahl was fluent in Syriac and Greek, the two sources for the medical tradition of antiquity, and versed in fine calligraphy.
His Firdous al-Hikmah ("Paradise of Wisdom"), which he wrote in Arabic called also Al-Kunnash was a system of medicine in seven parts. He also translated it into Syriac, to give it wider usefulness. The information in Firdous al-Hikmah has never entered common circulation in the West because it was not edited until the 20th century, when Mohammed Zubair Siddiqui assembled an edition using the five surviving partial manuscripts. There is still no English translation. A German translation by Alfred Siggel of the chapters on Indian medicine was published in 1951.
Tuhfat al-Muluk ("The King's Present")
a work on the proper use of food, drink, and medicines.
Hafzh al-Sihhah ("The Proper Care of Health"), following Greek and Indian authorities.
Kitab al-Ruqa ("Book of Magic or Amulets")
Kitab fi al-hijamah ("Treatise on Cupping")
Kitab fi Tartib al-'Ardhiyah ("Treatise on the Preparation of Food")
Firdous al-Hikmah is one of the oldest encyclopedias of Islamic medicine, based on Syriac translations of Greek sources (Hippocrates, Galen Dioscorides, and others).It is divided into 7 sections and 30 parts, with 360 chapters in total. 
Part I. general philosophical ideas, the categories, natures, elements, metamorphosis, genesis and decay.subdivided into I2 chapters, treats of general philosophical ideas, mostly following Aristotle.
On the Genesis of Things from the Elements, the Action of the Celestial Sphere and the Luminous Bodies therein.
On the Effects of the Action of the Elements on the Air and subterranean Conditions
On shooting Stars and the Colors which are generated in the Air. (rainbows)
Part II embryology, pregnancy, the functions and morphology of different organs, ages and seasons, psychology, the external and internal senses, the temperaments and emotions, personal idiosyncrasies, nervous affections, tetanus, torpor, palpitation, nightmare, the evil eye, hygiene and dietetics.
Part III. Treats of nutrition and dietetics. 3 chapters
Part IV. (The longest,107 out of 276 folios and 152 chapters. Each chapter is short, often less than one page and seldom more than two. There is little beyond the signs and symptoms of each disease and the treatment recommended there are no references to actual cases, or clinical notes. ) general and special pathology, from the head to the feet, and concludes with an account of the number of muscles, nerves and veins, and dissertations on phlebotomy, the pulse and urinoscopy.
Book 1 (9 chapters) on general pathology, the signs and symptoms of internal disorders, and the principles of therapeutics.
Book 2 (14 chapters) on diseases and injuries of the head; and diseases of the brain, including epilepsy, various kinds of headache, tinnitus, vertigo, amnesia, and nightmare.
Book 3 (12 chapters) on diseases of the eyes and eyelids, the ear and the nose (including epistaxis and catarrh), the face, mouth and teeth.
Book 4(7 chapters) on nervous diseases, including spasm, tetanus, paralysis, facial palsy, etc.
Book 5 (7 chapters) on diseases of the throat, chest and vocal organs, including asthma.
Book 6 (6 chapters) on diseases of the stomach, including hiccough.
Book 7 (5 chapters) on diseases of the liver, including dropsy.
Book 8(14 chapters) on diseases of the heart, lungs, gall-bladder and spleen.
BooK (19 chapters) on diseases of the intestines (especially colic), and of the urinary and genital organs.
Book10 (26 chapters) on fevers, ephemeral, hectic, continuous, tertian, quartan and semi-quartan ; on pleurisy, erysipelas, and small-pox ; on crises, prognosis, favorable and unfavorable symptoms, and the signs of death.
Book 11(13 chapters) on rheumatism, gout, sciatica, leprosy, elephantiasis, scrofula, lupus, cancer, tumours, gangrene, wounds and bruises, shock, and plague. The last four chapters deal with anatomical matters, including the numbers of the muscles, nerves and blood-vessels.
Book 12 (20 chapters) on phlebotomy, cupping, baths and the indications of the pulse and urine.
Part V. of tastes, scents and colors. 1 book, 9 chapters
Part VI materia medica and toxicology.
Part VII. climate, waters and seasons in their relation to health, outlines of cosmography and astronomy, and the utility of the science of medicine: and a summary of Indian Medicine in 36 chapters.
On the Quran he said: "When I was a Christian I used to say, as did an uncle of mine who was one of the learned and eloquent men, that eloquence is not one of the signs of prophethood because it is common to all the peoples; but when I discarded (blind) imitation and (old) customs and gave up adhering to (mere) habit and training and reflected upon the meanings of the Qur'an I came to know that what the followers of the Qur'an claimed for it was true. The fact is that I have not found any book, be it by an Arab or a Persian, an Indian or a Greek, right from the beginning of the world up to now, which contains at the same time praises of God, belief in the prophets and apostles, exhortations to good, everlasting deeds, command to do good and prohibition against doing evil, inspiration to the desire of paradise and to avoidance of hell-fire as this Qur'an does. So when a person brings to us a book of such qualities, which inspires such reverence and sweetness in the hearts and which has achieved such an overlasting success and he is (at the same time) an illiterate person who did never learnt the art of writing or rhetoric, that book is without any doubt one of the signs of his Prophethood."
^Siggel, Alfred (1951). Die indischen Bücher aus dem Paradies der Weisheit über die Medizin des' Alī ibn Sahl Rabban al-Ṭabarī. Übersetzt und erläutert. Wiesbaden: Akademie der Wissenschaften und der Literatur.
^`Alî at-Tabarî's ``Paradise of Wisdom, one of the oldest Arabic Compendiums of Medicine Max Meyerho Isis, Vol. 16, No. 1 (Jul., 1931), pp. 6-54 Published by: The University of Chicago Press on behalf of The History of Science Society Article Stable URL: http://www.jstor.org/stable/224348
^Alî at-Tabarî's ``Paradise of Wisdom, one of the oldest Arabic Compendiums of Medicine Author(s): Max Meyerhof Source: Isis, Vol. 16, No. 1 (Jul., 1931), pp. 6-54 Published by: The University of Chicago Press on behalf of The History of Science Society Stable URL: http://www.jstor.org/stable/224348 . Accessed: 04/10/2014 21:57|He extracted his summary from the books of CHARAKA (Arabic: Jarak), SUSHRUTA (Arabic: Susrud), the Nidana (Arabic: Niddin), and the Ashtafigahradaya (Arabic Ashtdnqahrada).