Many chiros are snake oil salesmen and many are hooked into some kind of miracle cure/MLM sales.
Our very very successful cousin from Switzerland came to the U.S. to attend
Chiropractic school and then developed his sales busness until he got out of patient care and now teaches the oil salesmen how to sell the snake:
http://www.practicewealth.com
And I love his advice about plantar fasiatis. There is not one iota of medical info in his piece:
http://www.footpainmarketing.com/
There are definitely some whackos out there who traded in their status as a medical official for supplement/homeopathy/other weird non-scientific endorsement deals. I saw a chiropractor a couple years ago while I was doing physical therapy on my neck. I was pleasantly shocked when he admitted "[the adjustment he gave me] will make you feel better for a couple days, but it won't cure you."
When I lived in Alberta 20 years ago, chiropractic was a kind of medicine considered to be on par with physiotherapy. Doctors would routinely refer patients for treatments, which were covered under the public health plan. However, there were some radical differences in how chiropractic was practiced and marketed.
First, the chiropractors freely admitted that the goal, and the only goal, of the treatment was to relieve pain temporarily by briefly manipulating joints slighty beyond their normal range of motion, so as to force fluid out of the joint (which creates the pop). This process would stop the negative feedback loop wherein muscle tension caused pain, which in turn caused more tension. If there was an underlying cause to the pain, they admitted that nothing they did would address the cause, and were very generous in their referrals to spinal specialists or physiotherapists. If the pain was caused by bad posture, for example, the treatment would do nothing to change the habit. Chiropractors were completely frank about this fact.
Second, the chiropractors did not attempt to diagnose injury or illness. If they saw symptoms consistent with, say, a ruptured disc or spinal stenosis, they were generous in their referrals to people qualified to treat such problems. There was no mention of this "subluxation" bunkum and no pretense that the bones of the spine had somehow become misaligned or dislocated. Nor were there extra-billed tests such as X-rays, because frankly the kind of subluxation they purport to treat cannot be diagnosed by X-ray (because it doesn't exist... for a normal person if your spinal bones were suddenly out of alignment you'd need a spinal surgeon and you'd most likely be paralyzed.)
Third, the benefits of chiropractic were not exaggerated the way I see them exaggerated in the States. People didn't claim to be able to cure diabetes, epilepsy, blindness, migraines, allergies, or immune disorders through chiropractic.
Fourth, there was no attempt to sell chiropractic as a maintenance therapy such that people were encouraged to come in for regular spinal manipulations for health. It was not marketed as appropriate for children or infants without a doctor's referral.
Fifth, there was no overt advertising of the chiropractic, nor was the practice used to advertise other products or services although it was permissible for different kinds of specialists to exchange business cards to go along with the referrals given.
How exactly did the industry achieve such a level of professionalism? Well, there was a list of authorized treatments eligible for reimbursement out of the provincial health plan funds. The only kind of treatments authorized for payment were joint manipulations for temporary relief of pain. "Subluxation" treatments and other happy nonsense weren't covered, and neither was snake oil.
Basically the province said: "we're only paying for medical treatments that have been proven and verified by the medical community. If you want to sell supplements, homeopathy, tin-foil hats or other kinds of unproven pseudoscience, go for it. But we're not paying for it out of the public purse, you may not combine the two practices if you expect to keep your license. So pick one. Oh, and by the way, if you have a medical credential and maintain a licensed medical practice on paper but use it to sell snake oil instead, and the snake oil harms someone, expect to be charged with a criminal offense because you're held to a higher standard due to your education and knowledge. Meanwhile, we support your malpractice insurance carrier's right to exclude snake oil related expenses from your coverage."