This is a more involved study of hypnosis fron the Mayo Clinic. The original Mayo brothers were very interested in hypnosis. Click on the above link to read the whole article with references to over 140 articles of research.
The article concludes:
The acceptance of hypnosis as a mode of treatment in medicine is increasing as a result of “careful, methodical, empirical work of many research pioneers.”35 Many important trials reviewed here have helped to establish the role of hypnosis in contemporary medicine. These trials have established the utility and efficacy of hypnosis for several medical conditions, either alone or as part of the treatment regimen. Nonetheless, skepticism may prevail and hypnosis may remain underused because of the tendency to doubt or fear the unknown. According to a recent study, health care providers changed their attitudes significantly and positively when presented with information about the use of hypnosis in medicine.144 Through greater awareness and acceptance of hypnosis, additional training and research can be inspired in pursuit of improved techniques and new areas of potential benefit.