Distinction between Hypnosis and Samadhi 

Therefore it is extremely important to distinguish between hypnosis and samadhi, and learn to avoid entering the hypnotic state, before we begin meditation. This is the meaning of the well known Zen saying, "If you see the Buddha on the way, kill him." "Buddha," there, is the hallucination. "Kill," there means, destroy it. There is nothing bad about hypnosis, unless it is used for bad purposes. Sometimes it can even be used for medical purposes like healing some sicknesses. In ancient times, hypnosis was used by doctors to anesthetize patients before operation. Some use it in psychotherapy. Yet true Buddhist meditation is not hypnosis. Samadhi is not concentration or self hypnosis.