Avicenna (980-1037 AD)
In India, Unani system of Medicine was introduced by Arabs and soon it took firm roots in the soil. When Mongols ravaged Persian and Central Asian cities like Shiraz, Tabrez and Galan, scholars and Physicians of Unani Medicine fled to India. The Delhi Sultan, the Khiljis, the Tughlaqs and the Mughal Emperors provided state patronage to the scholars and even enrolled some as state employees and court physicians. During the 13th and 17th Century Unani Medicine had its hey-day in India. Among those who made valuable contributions to this system into period where Abu Bakr Bin Ali Usman Ksahani, Sadruddin Damashqui, Bahwa bin Khwas khan, Ali Geelani, Iqbal Arzani and Mohammad Hashim Alvi Khan.

Unani Medicine is a Traditional Medicine, which like other Traditional Medicines, e.g., Ayurvedic Medicine and Traditional Chinese Medicine, has a specific and unique set of principles and methods that are used in the diagnosis and treatment of health conditions.
Unani is an Arabic word that refers to its origins in Ionia in ancient Greece, as Unani Medicine is primarily based on the ancient methods of medicine that were used and taught by its traditional founders.
Unani Medicine is both very old and very modern. As we have seen, it was practised by Hippocrates over 2400 years ago. His medicine however included a great deal of ancient Egyptian medicine as well as important components of the ancient Mesopotamian traditions. Thus it can be said that many aspects of Unani Medicine are over 6000 years old.Unani Medicine is also very modern, as it has been and is still being practised as a traditional medicine in Europe, 

the Middle East and the Asian subcontinent. Although in Europe traditional medicine has, to a great extent, been supplanted by modern medicine, there are still those who are knowledgeable in, and practise Unani Medicine. In the Middle East and in the Asian Subcontinent, Unani Medicine continues to serve millions of people as their only or main traditional medicine. Further, as modern medicine also originated from the ancient Greek traditions, new scientific concepts can readily be integrated into its practises. Thus Unani Medicine is both an ancient medicine and the traditional medicine of the future. 

Unani Medicine teaches that Natural Systems, which includes the human body, are simply too complex to ever be understood as a whole, by only looking at their individual component parts. Thus Unani Medicine uses a holistic set of principles that make it easy for a practitioner of Unani Medicine to turn a diagnosis into a treatment procedure.

In Unani Medicine there are two aspects or principles that are very important; these are i. the life force or thymos (also called pneuma by some authors) and ii. the four vital essences or humors. In disease the thymos or the humors may be affected in various ways: there may be too little thymos or life force, or too much in the body or in a part of the body. The life force or thymos is primarily affected by the emotions, but can also be affected by age or disease. Problems with the humors are considered the most common however, and these may occur from having too much of one or more humors in the body or in a part of the body, or too little of a humor, or the humor may be corrupted by a poison or an invasive micro-organism. Humors are affected to some extent by the life force, or thymos, and to a greater extent by the food we eat, the beverages we drink and by external influences, such as the environment.

Treatment usually involves some dietary approaches, but in most cases includes Herbal Medicine, which in the case of Unani Medicine also includes mineral substances. Generally also some work will be done on specific body reflexes, most commonly by massage; but in the case of musculoskeletal problems (e.g. arthritis, back pain) also by manipulation or by the application of cold, heat or suction cups. Serious and acute diseases may in rare instances be treated by puncturing certain reflex points, during which a few drops of blood are released.

Hippocrates believed that whenever and wherever possible, medicine should be gentle and safe, and this is the main objective of Unani Medicine. In Unani Medicine, thousands of years of experience, and its practice by some of the greatest minds the world has ever known, have ensured that it is not only a safe and gentle medicine, but has unsurpassed efficacy in the treatment of many acute and chronic conditions.