RESUMO
Abstract Before the Oriental medical theories were established as the theoretical and methodological guidance of Traditional Mongolian Medicine, medical knowledge of Mongolians: healthy lifestyle, diagnosis and treatment methods were based on the law of the unity of opposites. The classic example of contrast of things, relationship between hot and cold determines their union and fight with dynamic interaction of two absolute energy forces. The universe is closely related to the power fluctuations of changes in hot and cold (arga and bilig) and its important base, law of interdependence. Humans and thousands of nature substances exist in contrasting flow of the sun and moon. The nature, climate and seasons change following this principle, too. The hot and the cold are within divided into hot and cold as well. In other words, it is the same concept as the cold is in arga and the hot is in bilig. Things and substances are divided into two like this and they are born and die by contrasting nature. For example: it is divided as hotness of the day and coldness of the night while before noon as hotness in arga, afternoon as coldness in arga, before midnight as coldness in bilig and after midnight as hotness in bilig. The theory of hot and cold is a general law of all the things of the universe. Human is an integral element of the universe as it is the living part of it. Therefore, it has the essence of hot and cold and creates harmony. Furthermore, with this research, we tried to clarify the idea that the principle of hot and cold is two sides of biology.