Physiological Roles, not Structure will Categorize Placement of Molecules in Humours (Akhlat) in Unani Medicine: The Case of Human Haemoglobin

Greeko-Arab medicine or Unani medicine is an ancient system of medicine which is widely practiced in the Indian subcontinent and beyond. This system of medicine is based on the theory of humours, which places body fluids into four classes. This paradigm when considered on the basis of modern sciences, calls for identifying biomolecules which constitute the four humours. Using the example of human haemoglobin, we make the argument that the chemicobiological/physiological roles of the molecules and not their structure will be the rationale for placing molecules in the four humours. The discussion presented here will form the basis of scientifically understanding this ancient system of medicine, and will pave way for further research in this area.