Tibb (Medicine) is art and science of life, dealing with the maintenance of health and the prevention as well as cure of disease. In Unani System of Medicine (USM) the concept of Asbab Sitta Daruriyya (six essential factors) is a well-known concept that can help in the prevention of many diseases which are the result of poor management of these factors. These factors have significant impact on human body and responsible for the preservation of existing health. Nobody could escape from these factors during their life. Any disproportion in these factors may cause disease. Concept of Akhlat (humors) is a key concept in Umur Tabi‘iyya (seven basic principles) and occupied a central place in Unani Medicine. Sihhat and Marad (health and disease) are generally related with Akhlat (humours). So Khilti Sihhat can be defined as that condition in which Akhlat (humors) are present in harmony in respect of kammiyat wa kaifiyat (quantity and quality). Any type of alteration in quantity or quality of one or more Khilt may cause diseases in the body. Each Khilt is related to a specific season, diet, age, and constitution of the human body. Any alteration produces adverse effects over the human body. Seasonal changes come in context of Taghayyurat tabii (normal changes) of Hawa Muhit (air) which is one among six essential factors. Classical textbooks of USM are enriched with the adverse effects of variation of Fusul Arba‘a (four seasons) on human body. This paper will elucidate the relation of Fusul Arba‘a (four seasons) and Akhlat Arba‘a (four humors) and its affection on the human body.
