OBJECTIVES: Oriental medicine has affected the way in which Koreans seek psychiatric help and how they understand psychiatric symptoms and mental illnesses. In this study, we investigated the concept of psychosis in traditional oriental medicine and compared it with how modern western medicine understands the same concept. METHODS: We searched for descriptions of psychotic symptoms or illnesses in traditional medical documents of various periods. Four psychiatrists then analyzed the contents of these descriptions in terms of DSM-IV. RESULTS: The concept of psychosis in oriental medicine has two symptom domains: positive and negative symptoms, which are similar to the positive and negative symptoms of schizophrenia in modern psychiatry. However, there were differences in the basic concepts of disease entities and in the approaches to the illness. CONCLUSION: This descriptive study showed that, in oriental medicine, psychopathology is based on oriental philosophy, and that this creates wide differences between oriental and western medicine.