Qigong as a part of the traditional Chinese medicine is similar to western "meditation", Indian "Yoga" or Japanese "Zen", which can all be included in the category of traditional psychotherapy. A series of physiological and psychological effects occur in the course of Qigong training, but inappropriate training can lead to physical and mental disturbances. Physiological effects include changes in EEG, EMG, respiratory movement, heart rate, skin potential, skin temperature and finger tip volume, sympathetic nerve function, function in stomach and intestine, metabolism, endocrine and immunity systems. Psychological effects are motor phenomena and perceptual changes: patients experienced warmness, chilliness, itching sensation in the skin, numbness, soreness, bloatedness, relaxation, tenseness, floating, dropping, enlargement or constriction of the body image, a sensation of rising to the sky, falling off, standing upside down, playing on the swing following respiration, circulation of the intrinsic Qi, electric shock, formication, during Qigong exercise. Some patients experienced dreamland illusions, unreality and pseudohallucination. These phenomena were transient and vanished as the exercise terminated. Qigong deviation syndrome has become a diagnostic term and is now used widely in China.