Certain people have adopted the Freudian belief that the subconscious mind contains all the past trauma. When they combine this belief with information about hypnosis, as working directly with the subconscious mind, the conclusion tends to go something like this: "Wouldn't I risk that hypnosis opens a gate in the subconscious mind that will start an endless flow of unpleasant memories from the past?". To this day I have never experienced nor heard about such things.

My experience is that you should adopt a different view of the subconscious mind. The literature will show you again and again, that when a client comes to hypnotherapy the subconscious mind is preserving the problem, because it acts on beliefs about how the world functions, the solution to the problem will often be straightforward. Many times the unconscious mind can simply be asked to find another way of achieving the same goal, that doesn't include the problem state as a sideeffect.

So will unpleasant memories surface when you are hypnotized? I can't really give an answer to that question, because the unplesant memories will sometimes be the key to positive change. It should be the task of the hypnotist to make sure that every unpleasant memory experienced in hypnosis is treated in an appropriate way, so the client doesn't leave the hypnotherapy feeling worse than when he came (If this happens please tell the hypnotist, as this person is there to help you!).