Ali ibn Abbas al-Majusi, also known as Masoudi, was a famous Persian physician.
His Latin name was Ali Abbas or Haly Abbas, and was born in Ahwaz, southwestern Persia. He flourished under the Buwayhid Amir Adhad al-dowleh, and died in 994.
Known to Europeans as Holy Abbas, Majusi was from a Persian family with Zoroastrian forebears, though he himself was a Muslim.
He is considered one of the three greatest physicians of the Eastern Caliphate in his time. He studied under Shaikh Abu Maher Musa ibn Sayyār.
He wrote for Adhud al-dowleh a medical encyclopedia called The Complete Book of the Medical Art (Kitab al-Maliki, Liber regalis, Regalis dispositio; also called Kamil as-sina'a at-tibbiyya), which is more systematic and concise than Razi's Hawi, but more practical than Avicenna's Canon of Medicine, by which it was superseded. It was dedicated to Adhud al-Dawlah Fana-Khusraw.
The Maliki is divided into 20 discourses, of which the first half deal with theory and the other with the practice of medicine. Some examples of topics covered are dietetics and materia medica, a rudimentary conception of the capillary system, interesting clinical observations, and proof of the motions of the womb during parturition (e.g. the child does not come out; it is pushed out).