Before transpersonal psychology was introduced to Japan, psychiatrist Kiyoshi Kato was engaged in clinical practice in the same field. He was also involved in treatment of Schizophrenia and succeeded in adding a unique perspective to the treatment. Further to this, he attempted to determine the merit of usingpsychedelic drugs as part of psychiatric treatment. In these processes, he relied on his background knowledge and expertise he obtained about the altered state of consciousness through his contact with Catholic mysticism and Zen ritual. In his clinical practice, he came to the recognition that the psychedelic drug works more effectively as a tool of self awareness for the therapist than as a tool of direct treatment. As the use of psychedelic drugs became strictly restricted, however, so did he change his focus to art therapy and guided imagery therapy, and then to involvement in a kind of group therapy. As to transpersonal psychology, Kato took the issue of its weak philosophical and theoretical foundation, regarding it as a transient phenomenon. But his activity has demonstrated his empathy with the concern and practice of transpersonal psychology.