The study only looked at a sampling of the shows, 40 episodes from each from early 2013. Regardless, the findings are important, especially now, as Oz has come under fire for endorsing dozens of "quack" treatments.
Of all the advice dispensed on the 40 episodes of "The Dr. Oz Show" that the researchers studied, evidence supported just 46%.
The evidence also contradicted 15% of the advice given out on the show, and was not found for 39% of it.
Results for "The Doctors" were similar to those for "Dr. Oz," but slightly better. Evidence supported 63% of those recommendations, contradicted 14%, and was missing for 24%.
Of all the recommendations given out on the "The Dr. Oz Show," the study found the vast majority pertained to dieting and weight loss.
Oz was called to testify at a senate hearing last summer after he promoted the extract of green coffee beans as a "magic weight loss cure." His claim, it was later found, had only one scientific study to support it. That study was later retracted, partially because it was funded by the product's manufacturer.
Much of the other advice Oz has dispensed on his show lands firmly in the realm of wacky, according to many other doctors and scientific studies.
Oz has repeatedly brought several self-proclaimed "spiritual mediums" to the show as guests and shown the audience before-and-after brain scans to show them that the psychics attain a "different type of consciousness" when they "connect with the other side." Because the scans are done using an EEG, which simply shows relative activity in different areas of the brain, the "results" (meaning the difference in before and after scans) could show a variety of things, including elevated anxiety.
He's also endorsed homeopathy, super-diluted doses of medications that have been repeatedly shown to be ineffective. In 2005, medical journal The Lancet published a large study comparing homeopathic remedies and conventional medical treatments with placebos. They concluded that any effects of homeopathy were largely the same as those of placebos.
Responding to Reuters' requests for comment, Tim Sullivan, the director of publicity for "The Dr. Oz Show," said the show "has always endeavored to challenge the so-called conventional wisdom, reveal multiple points of view and question the status quo."
He added, "The observation that some of the topics discussed on the show may differ from popular opinion or various academic analyses affirms that we are furthering a constructive dialogue about health and wellness."
Sullivan did not respond to a Business Insider request for comment.