The Unani system of medicine owes, as its name suggests, its origin to Greece. It was the Greek philosopher-physician Hippocrates (460 – 377 BC) who freed Medicine from the realm of superstition and magic, and gave it the status of Science. The theoretical framework of Unani Medicine is based on the teachings of Hippocrates. After Hippocrates, a number of other Greek scholars enriched the system considerably. Of them, Galen (131–210 AD) stands out as the one who stabilized its foundation, on which Arab and Persian physicians like Rhazes (850–925 AD) and Avicenna (980–1037 AD) constructed an imposing edifice. Unani Medicine got enriched by imbibing what was best in the contemporary systems of traditional medicine in Egypt, Syria, Iraq, Persia, India, China and other Middle East and Far East countries. It also benefited from the native medical systems in vogue at the time in various parts of Central Asia. That is why this system is known, in different parts of the world, with different names such as Greco-Arab Medicine, Ionian Medicine, Arab Medicine, Islamic Medicine, Traditional Medicine, Oriental Medicine etc.
Unani system of medicine was introduced to India by the Arabs, and soon it took firm roots in the soil. The Delhi Sultans, the Khiljis, the Tughlaqs and the Mughal Emperors provided state patronage to the scholars and even enrolled some as state employees and court physicians. The system found immediate favour with the masses and soon spread all over the country. During the 13th and 17th century Unani Medicine had its heyday in India. Among those who made valuable contributions to this system in the period were, to name only a few, Abu Bakr bin Ali Usman Kashani, Sadruddin Damashqui, Bahwa bin Khwas Khan, Ali Geelani, Akbar Arzani and Mohammad Hashim Alvi Khan.
The scholars and physicians of Unani Medicine who settled in India were not content with the known drugs but they subjected Indian drugs to clinical trials and as result of their experimentation added numerous native drugs to their own system, thus further enriching its treasures. The system found immediate favour with the masses and soon spread all over the country and continued to hold an unchallenged sway for a long period even after the downfall of Mughal Empire. During the British rule, Unani Medicine suffered a setback and its development was hampered due to withdrawal of governmental patronage. But since the system enjoyed faith among the masses, it continued to be practiced. It was mainly the Sharifi Family in Delhi, the Azizi family in Lucknow and the Nizam of Hyderabad due to whose efforts Unani Medicine survived in the British period. An outstanding physician and scholar of Unani Medicine, Hakim Ajmal Khan (1868 – 1927) championed the cause of the Unani system in India. The Hindustani Dawakhana and the Ayurvedic and Unani Tibbia College in Delhi are the two living examples of his immense contribution to the multipronged development of the two Indian systems of medicine – Unani Medicine and Ayurveda.
The Majeedi family of Delhi, especially Hakim Abdul Hameed (1908 – 1999) made valuable contribution towards modernization of Unani drug industry. Hakim Abdul Hameed also established in New Delhi an Institute of History of Medicine and Medical Research (IHMMR) that developed into a deemed university – the Jamia Hamdard. Also, some other families such as the Niamathullah family of Madras (now Chennai) and the Usmani family of Allahabad (Uttar Pradesh) played significant role in the advancement of Unani Medicine in the 20th Century.