Hallucinations are illusory perceptions that are caused by brain dysfunction and nervous system disorders. Hallucinations are a common symptom in psychiatric patients. However, normal people sometimes have hallucinations under the effect of extreme fatigue, extreme fear, extreme hunger, prolonged loneliness and insomnia, and certain drugs. It may be that the exposure to certain things more, in the brain presents a certain suggestion. Or the heart is always hung up on the fear of things, or often appear things caused by hallucinations. The deficiency of qi and blood and the lack of vitamin B in the body may also lead to hallucinations.