AbstractIn Unani System of Medicine, humours (Akhlat) play a vital role in maintenance of health; imbalance of their proportion either qualitative or quantitative can cause disease. Akhlat refers to the body fluids under a wider perspective in the Unani Medicine, which also encompasses fluids designated as hormones by the Modern Medicine. Akhlat (humours) are those moist and fluid parts of the body which are produced after transformation and metabolism of the nutrition; they serve the function of growth, repair, produce energy, preservation of individual and the species. It is concerned with growth, multiplication, differentiation, and metabolic activities of different tissues and systems, and thereby maintains a correct physiological balance between them. Present paper is a review on the concept of Akhlat and an attempt to understand hormones.