The Ottoman scholar Akshamsaddin (Muhammad Shams al-Din bin Hamzah, 1389–1459) is remembered more often as the mentor and advisor to Sultan Mehmed II rather than as a physician who contributed remarkably to the medical knowledge of his time. Born in Damascus, he acquired in his youth a significant knowledge of medicine and pharmacology, derived from the works of the ancient Persian, Greek and Roman physicians, particularly of Hippocrates and Galen, later translated and expanded by Muslim scholars.

In the 15th century, Islamic medicine had already established a sophisticated understanding of human anatomy, disease processes, and therapeutics. This was characterized by its empirical approach, its emphasis on clinical observation, and the development of hospitals (bimaristans) for both patient care and medical education. While detailed records of Akshamsaddin’s medical education are limited, it is known that his expertise was recognized even at the Ottoman court, where he successfully treated Süleyman Pasha, one of the chief judges under Sultan Murad II, and later healed the daughter of Sultan Mehmed II.

Akshamsaddin’s most remarkable contribution was his early conception of what later become known as the germ theory of disease. In the 14th century, centuries before Pasteur and Koch, Akshamsaddin wrote about what he called “seeds of disease”—invisible entities that could cause illness. He described these as “seeds that are so small they cannot be seen but are alive.” This insight came at a time when the prevailing medical understanding was still largely based on the humoral theory of disease. Akshamsaddin’s conceptualization of living, invisible disease-causing agents remarkably presaged microbiology and the germ theory of disease that would not be scientifically proven until several centuries later.

Akshamsaddin documented much of his medical knowledge in his work Maddet’ül-Hayât (Material of Life), which served as a valuable resource for medicine, botany, and pharmacy. He detailed the composition of medicines effective against various diseases and described methods for extracting juices, essences, and oils from natural substances for pharmaceutical production. His work contributed to a systematic approach to medication, including the standardization of drug preparation, the classification of medicinal substances according to their properties, and the development of complex compound medicines.

Akshamsaddin also recognized the importance of hygiene, quarantine, and environmental measures in preventing the spread of infectious diseases. He advised isolation for infectious diseases, environmental sanitation, and personal hygiene as preventive strategies.

Akshamsaddin’s approach was to integrate the spiritual and physical dimensions of healing. He conceived medicine not merely as a technical practice but as part of a comprehensive understanding of human wellbeing that encompassed physical, mental, and spiritual dimensions, employing not only physical remedies but also spiritual practices such as prayer and meditation,

Following Akshamsaddin’s contributions, Ottoman medicine continued to develop its distinctive character while maintaining connections to the broader Islamic medical tradition. It evolved to include imperial medical schools, a hierarchical system of physicians led by the royal chief physician (hekimbaşı), and regulations for medical practice. Akshamsaddin’s influence can be seen in the Ottoman medical tradition’s continued integration of theoretical knowledge with practical clinical experience, its emphasis on empirical observation, and its openness to incorporating diverse medical traditions.

Akshamsaddin’s conception of invisible living agents causing disease emerged approximately 100 years before Fracastorius in Europe proposed similar ideas about “seeds” of disease in his work De Contagione et Contagione Morbis (1546). The hygienic practices and hospital-based care championed in Ottoman medical institutions stood in stark contrast to the often unsanitary conditions and limited medical facilities in much of medieval Europe. Islamic hospitals had already developed specialized wards, outpatient services, and pharmaceutical divisions centuries before comparable developments in Europe.

Evaluating Akshamsaddin’s contributions presents several challenges. First, there is the limited preservation and translation of primary sources, making it difficult to fully assess the scope and details of his medical work. Moreover, the history of medicine in the Islamic world, including Ottoman contributions, has often been marginalized in Western-centric historians, leading to an underappreciation of figures such as Akshamsaddin. Recent scholarship has begun to address this imbalance, reassessing the contributions of Islamic physicians to the development of modern medicine.