Has anyone had experience with using magnets to treat headaches?

My wife has had horrible headaches on and off for about two years. She has done everything she should do -- MRIs, cat scans, consultations with neurologists, etc. She has been taking medication -- actually something that is a blood pressure medication -- Inderol -- that has kept them away for the most part. But recently they started reoccurring. The recommendation of her doctor was to just increase her dosage. She's reluctant to do this. She also sees a chiropractor who gave her a magnet tapped to the back of her neck. Her headaches did seem to subside. Now generally I think this would be absolute quackery, but I won't argue with success. Has anyone out there had similar experiences? Medical professional -- do you have an opinion about this? Thanks for all insights?