Abstract3.1 Introduction3.2 Some Notions of Fuzzy Logic3.3 A Diagnosis of Disease Syndromes of Traditional Vietnamese Medicine3.4 An Inference Model of Diagnosis of Disease Syndromes in Traditional Oriental Medicine3.5 An Example of Combining Positive and Negative Rules3.6 Application of the Model for Developing a System of Eight Syndrome Diagnosis3.7 ConclusionsAppendix 3.1 Examples of Basic symptoms for Eight SyndromesAppendix 3.2 Basic Rules for Eight Syndrome Diagnosis