Medicine, defined as the science and practice of the diagnosis, treatment and prevention of disease. The word medicine springs from Latin medicus, meaning “physician″. According to Henry Sigerist, the medical historian has stated that every culture had developed a system of medicine and medical history is but one aspect of history of culture. India, with its rich cultural heritage, has been in the forefront in contributing to the medical sciences, and there is plenty of proof of the same. Ayurveda, Yoga and Naturopathy, Unani, Siddha, and Homeopathy (AYUSH) is one component of the six indigenous systems of medicine practiced in India. The art of tending to the sick is as antique as the humanity itself. The ancient civilizations probably knew about the functions, physiology and anatomy of the human physique in surprising details, and their art of tending the sick remains an evidence of their knowledge. The medical systems that are truly Indian in origin and development are Ayurveda and as well the Siddha system. Unani-Tibb and Homeopathy, though not of Indian origin, have a significant importance in health care in India. Today, India is among the leading countries as far as the practice of Unani medicine is concerned. This paper will be an attempt in analysing the insights of various fundamental principles and key concepts of Unani, Ayurveda, Siddha and Homeopathy along with their differential aspects.