Therapists have defended their use of complementary medicines after a cancer expert said patients needed protection from "exploitation".
Experts have called for the treatments to be reclassified
Professor Jonathan Waxman, of Imperial College London, wants laws against "the snake oil salesmen that peddle cures and exploit the desperate".
But Dr George Lewith, who has studied the use of complementary medicine, said most patients find it "helpful".
He said professor Waxman's view was interesting but it was a personal one.
In an article for the British Medical Journal Professor Waxman said: "Claims made by companies to support the sales of such products may be overtly and malignly incorrect."
He called for them to be reclassified as drugs, rather than food supplements, so they would be subject to pharmaceutical testing.
Professor Waxman also said that when treatments are unsuccessful "the patient has failed, not the alternative therapy, and the patient has let down the alternative practitioner".
Dr Lewith, of Southampton University, worked on a government-funded study on the use of complementary and alternative medicine (CAM) in cancer patients that was published earlier this year.
He said their information showed that CAM was used for around 30% of cancer patients.
"Our.. survey did not find these patients are anti-conventional medicine or using wacky diets," he said.
Responding to the call for legislation to regulate the industry Dr Lewith said: "You're starting from an assumption that is not grounded in fact."
Supporting Dr Lewith, Beverly Martin, a trustee of the charity the Institute for Complementary Medicine (ICM), said the treatment of cancer requires "training of the highest standard" whether conventional or complementary.
"There are published cases suggesting the great benefit to some patients of naturopathic treatment including radical detoxification and dietary changes," she said.