I used it to stop smoking 13 years ago and it worked. I had to play a tape every night for a month as I was going to sleep, but the subconscious message worked for me.
I also used it with a hypnotherapist 20 years ago to "cure" my allergies and had amazing success. I was almost nonfunctional with all of the allergy medications that I was taking and to this day I only have mild reactions at times to certain cats. The treatment was over several months going 2 or 3 times a week. He would hypnotize me and I would answer questions going back in my life to try & see when they started and how they were reinforced by outside stimuli, or my own internal voice telling me I was allergic to grass, dogs, cats, food, etc. The only thing that it hasn't worked for that I tried is food. That seems to be a toughie for most people.