Hypnotherapy can be used for more than just entertainment - it can help people quit smoking, sleep at night and feel less anxious.
But it won't cure obesity as you can't stop people from eating, Wellington doctor Pat McCarthy says.
He has a 65 per cent hit rate in patients giving up cigarettes after about three sessions and an 85 per cent success rate in people overcoming anxiety and insomnia.
Dr McCarthy left Scotland in 1986 after qualifying as a GP to practise in New Zealand.
"In 1996 I was the first doctor to set up a medical hypnotherapy practice.
"If you had said to me then that in 2013 I would still be the only one, I would've been gobsmacked."
He has developed a technique, which involves people putting themselves into a 60-second trance when they get the urge to smoke.
"What that means is the only thing you're losing is tobacco wrapped in paper and that's not a big loss.
"The problem with taking smoking away from someone is they get a grief reaction because even though at one level they want to stop smoking, what the smoking gives them is time out, relaxation, a break, a procrastination tool.
"I think they get a grief reaction from losing all that."
Dr McCarthy said it was "scary" that there were regulations for hypnotherapists.
"I think hypnotherapy has still got this name about it of being slightly dodgy and I think the stage shows make my job so much harder. There's a couple of Christian fundamentalist GPs who are very concerned . . . they think that I tell evil spirits to enter people."
New Zealand Medical Association deputy chairman Mark Peterson said hypnotherapy fell into the same category as acupuncture and other complementary treatments.
Wellington mother Lisa Antonopoulos, 48, began smoking when she was in her late teens.
She had smoked a packet a day, apart from a hiatus while she had her two daughters in her early 20s, and had failed at dozens of attempts to quit over the years.
"I honestly tried everything."
The account manager had not smoked a cigarette since seeing Dr McCarthy in 2011.
A mass hypnotherapy session will be held by Dr McCarthy to mark World Stop Smoking Day on May 31 and those that don't quit will get the $100 fee refunded.
- The Dominion Post
Should fluoride in water be the responsibility of central government?