Caffeine is one of the most widely consumed psychoactive substances in the world due to its stimulating effects on central nervous system. Caffeine mainly exerts its effects through a non-selective antagonism of adenosine receptors in different systems. A great number of studies have been investigated on this mechanism and found that caffeine is associated with not only central nervous system but also almost all the systems in human body. The purpose of this thesis is to provide a comprehensive analysis of caffeine from the pharmaceutical point of view. We will explore the chemical properties of caffeine, its pharmacological effects on the human body, and its therapeutic uses in medicine. Additionally, we will discuss about the potential risks associated with caffeine consumption.