Unani system of medicine also known as Greek-o-Arab medicine it is one of the popular traditional systems of medicine and well known for its unique concept and rational approach for exploring the unsolved and difficult problems related to health and diseases. Among various concepts of Unani system of medicine one of the sole concept is of Harārat gharīziyya. It is defined as natural heat which is endowed in the body at the time of conception and exists up to the entire life. This heat is associated with a fluid known as Ruṭūbat gharīziyya (innate moisture) and every individual receives this Ruṭūbat from parents. Performance of all important functions is concerned with innate heat such as digestion, metabolism, growth, development, replenishment of dissolute substances etc. When Harārat gharīziyya deviates from its normal level produces serious pathological conditions in the body. In this review the basic concept of Harārat gharīziyya and its importance in human body will be discussed in detail.
