Imagine going into surgery and instead of being given anesthesia, you are guided through self-hypnosis. Sound crazy? Well, it might not be.

For thousands of years, hypnosis has been used to treat patients suffering from chronic pain. Today, some surgeons are beginning to take hypnosis one step further, using it instead of drugs during operations. It's an intriguing method for patients who fear anesthetics could lead to side effects, even death.

Dr. Elvira Lang, associate professor of Radiology and Medicine at Harvard Medical School, pioneered recent studies that suggest hypnotherapy is extremely effective in controlling pain during surgery. The following are questions often asked about this treatment:

Q: I'm not sure what to make of hypnosis. What is it?

A: Hypnosis is a technique to help a patient reach a focused state - just like getting absorbed in a book. A therapist guides the patient to enter into a hypnotic "trance," similar to daydreaming, where the patient focuses on the sights, sounds, and sensations he or she wants to experience.

It involves relaxation, concentration, and a willingness to be helped. Despite popular belief, a hypnotherapist cannot make you do something you would not agree to do consciously.

Q: How can hypnosis work during surgery?

A: A specially-trained nurse or hypnotherapist guides the patient into a trance, usually while conveying very specific "anti-pain" messages to the patient.

While in the trance, the patient becomes so focused on positive, "pain-free" words and images that he or she is able to mentally filter out any sensations of pain. The patient may still be aware of the stimuli, but can filter out the hurt.

Painful stimuli are experienced as acceptable - analogous to bodily insult during sports, which under other circumstances we would wildly complain about.

Q: What if hypnosis doesn't work or wears off before the surgery is done?

A: During surgery, hypnotic techniques should be used only by a procedure team that is also experienced in treating pain and anxiety by medication.

Usually a combination of medication and relaxation works well. Studies show, however, that most patients who use hypnosis, with or without some anesthesia, are more relaxed and experience less pain throughout the duration of the surgery compared to patients who don't use hypnosis.