As practices of altered states of consciousness (ASC) have become more widely used among psychotherapists who have become aware of the limitations of psychoanalytic, educational and behavioral approaches, negative aspects ('Makyo') of ASC have drawn their special attention. For the purpose of controlling or preventing these side-effects, (1) the problem of indication is most important, (2) and evaluation of the patient's personality is indispensable, (3) preparatory education about ASC methods and (4) guidance by experienced leaders are most helpful, (5) appropriate use of tranquilizers and (6) the mere presence of a supportive therapist at the place of practice can also be helpful.