Using medical manuscripts and texts from the Byzantine period (330-1453), this article describes various, to date little discussed, aspects of Byzantine nosology, public health and therapeutics. Many diseases in the Byzantine era were widespread and had a high morbidity such as respiratory diseases, various kinds of anaemia, pestilential diseases (e.g. quartan fever, plague, dysentery and cholera), parasitic diseases, orthopaedic, rheumatic and psychiatric disorders, trachoma and alcoholism. Other very serious and relatively frequent conditions included leprosy, mania, gout, cancerous tumours and ulcers. Important elements of nephrology and various renal diseases were described and investigated, such as acute and chronic renal failure, acute and chronic nephritis, pyelonephritis, necrotic renal diseases, crush syndrome, and ulcers of the kidneys, i.e. tuberculosis or renal tumours. The microhistology and physiology of the kidneys were first studied by Oribasius, who discerned the existence of the capillaries – τpiχoΕiδη – some centuries before Malpighi. He also correctly described the blood circulation, general and pulmonary, as a precursor to Harvey. The first hospitals were organised during the Byzantine period, and the practice of Byzantine medical science and its social applications were regulated by a special medical legislation and deontology. Byzantine medicine was fruitfully connected with the Christian faith and developed the supreme model of the saints unmercenary – ávápγυpoi -physicians such as Cosmas and Damian (3rd century), Panteleemon (3rd-4th centuris) and the women physicians and miracle-worker saints, Zenais and Philonilla (1st century), the ‘friends of peace’, and Hermione (lst-2nd centuries).