There has been various approaches to use computer in medical consultation. Expert medical consulation is a problem-solving process that draws on a rich, though incomplete, body of knowledge that is both empirical and conceptual in nature. Much of Artificial Intelligence research has focused on determining the appropriate knowledge representations to use in order to achieve high performance from knowledge-based systems. In his thesis, A knowledge-based medical consultation system for diagnosing Dysmenorrhea in Gynecologics, with its knowledge representation and drawing inferences method, is introduced.