The study, presented in The New England Journal of Medicine looked at one of America's most common complaints -- lower back pain.
Researchers found that chiropractic manipulation and a certain type of physical therapy did benefit patients, but the results were only marginally greater than those of patients given a pamphlet about back pain.
Both therapies cost about $300, while the pamphlet cost a dollar.
Although chiropractors have been considered alternative, they are now the third largest group of health professionals in the United States after medical doctors and dentists.
Chiropractors believe that by manipulating the spine and aligning it, you can relieve a lot of problems and complaints of patients.
Some doctors claim that chiropractic manipulation can deal with everything from asthma and blood pressure to ear infections and bed-wetting.
A second article published in the Journal Thursday looked at asthma in children to see if chiropractic manipulation will help them.
"The answer is no. There was no benefit at all," Dr. Healy says.
The asthma study was conducted on 80 children with mild to moderate symptoms. All of the children received four months of treatment. One group received standard chiropractic treatments, while another underwent sham manipulations that were intended to feel like the real thing.
While both groups got slightly better, there was no difference between them.
Chiropractors are not considered medical doctors, Dr. Healy says. They don't believe in medicine or surgery, but espouse self-healing with the additional help of the manipulation of the spine.
Although controversial, chiropractice has been shown in past studies to speed recovery from a sore back.
"I am very convinced by the studies today as well as other studies that show that it is and can be beneficial for lower back pain," says Dr. Healy. "Where I would draw the line is moving into areas where there is no scientific evidence whatsoever and where there is no plausible biological basis for doing it, like ear infections or asthma."
While the medical world may not be ready to accept alternative medicines, the public has been spending billions of dollars on other forms of treatment for their ailments, Healy says.
Regardless of the findings of both studies, some chiropractors say that the most notable fact is that the research was conducted at all -- a sign, perhaps, of cautious acknowledgment by the medical community.