Doctors are calling for a government clampdown on hyperbaric oxygen clinics that are making claims they can treat autism, aging and AIDS.

Physicians in the public system say private clinics are advertising expensive services for dozens of medical conditions, even though there's little or no scientific evidence to back them up.

The doctors also warn that using privately run chambers, which are governed by few safety regulations, could be dangerous.

"We have people, in my view, practising medicine without a licence," said Dr. David Harrison, medical director of British Columbia's only public hyperbaric oxygen clinic.

"You could go out tomorrow and buy a hyperbaric chamber and put it in your garage and offer to diagnose and treat patients with hyperbaric oxygen and do exactly the same thing that I do, and charge them for it -- and nobody would come after you."

The little-known specialty of hyperbaric medicine, which delivers 100-per-cent oxygen to patients in a pressurized chamber, produces convincing results in treating patients for about a dozen conditions. Those include chronic wounds and carbon-monoxide poisoning.

But private clinics across the country continue to offer far more than Health Canada says the technology has been scientifically proven to deliver.

One operator, for instance, insists he can knock AIDS into submission for as little as $4,000.

The director even says the healing technology helped a little girl with virtually no brain to the point that she could learn how to ride a bike.

Harrison, meanwhile, wants the government to ensure chambers are inspected regularly, practitioners are trained to respond to emergencies and that patients are told about hyperbaric oxygen's risks and limitations.

"The off-label use of hyperbaric oxygen by private chambers is a real issue because we feel that it not only has a potential to harm patients, but it has the potential to damage the credibility of the specialty," Harrison said.

"There's a real suspicion that's in the medical community about whether or not hyperbaric oxygen really does something or whether we are just snake-oil vendors."

The Vancouver General Hospital physician treated someone who was injured in a private clinic several years ago. He has also seen patients who were misdiagnosed at those facilities.

It prompted him to demand that B.C.'s Health Department establish guidelines for all hyperbaric oxygen.

The College of Physicians and Surgeons of British Columbia has since joined his fight. In response, the province set up a task force last fall and is currently examining an issue that could affect people across the country.

Health Canada follows the recommendations of the Undersea and Hyperbaric Medical Society in recognizing it as an effective treatment for 13 medical conditions, including flesh-eating disease, diabetic foot ulcers and chronic, non-healing wounds.

In B.C., like other provinces, public health care only pays for the treatment of these recognized ailments.

At this stage, anything else should be considered experimental, even if it has shown positive results, Harrison said.

"Being treated with hyperbaric oxygen for unproven conditions, that's essentially a form of harm," said Harrison, adding that rare side effects of the therapy include seizures, collapsed lungs and heart attacks.

Hyperbaric medicine is very safe as long as precautions are taken, he said.

But a lack of tighter safety regulations or an adequately trained team of technicians can increase the chances of fire, a preventable, yet extremely rare, danger.

Last year, a fire erupted in a private hyperbaric chamber in Florida, killing a woman and her grandson, who was being treated for cerebral palsy, an off-label condition.

B.C. isn't the only province where hyperbaric doctors in the public system are expressing concern over private chambers.

A Toronto General Hospital physician who has been practising hyperbaric medicine for close to 30 years said people should refrain from spending big money to treat autism in the oxygen chambers.

"It doesn't work and to me it's unconscionable that anyone would exploit these desperate parents," said Dr. Ted Sosiak, who believes private operators shouldn't be allowed to treat anything but the 13 approved conditions.

"There are specific indications that have scientific evidence to support the usage and that's what people should stick with or they're wasting their money and their time."

But the director of a private hyperbaric clinic in B.C., which has treated more than 5,000 people over the last 13 years, indicated he's seen amazing results for off-label conditions.

"You can keep an AIDS patient alive for virtually ever using hyperbarics," said Humphrey Killam, director of Victoria's HOC Hyperbaric Care Center.

He said that after 40 sessions in the chamber, AIDS was rendered undetectable in two of his patients.

Killam called it an impressive accomplishment for a disease he insists is man-made.

"You've got to fight something that's genetically engineered to do you in," said Killam, who charges $100 per 90-minute session, with most patients taking 40-50 treatments.

He admitted that results vary and said hyperbaric oxygen doesn't work for everyone.

But he said some results are spectacular, including the case of a girl who had undergone scans that showed she virtually had no brain.

She couldn't even walk when she first arrived at the clinic, but things had changed dramatically after 40 dives in the tank, he said.

"Put it this way, seeing her out in a field with a bunch of kids you couldn't tell there was anything wrong with her," Killam said.

"She could walk down a curb without falling off, ride a bike, everything, except she still couldn't talk right.

"But pretty amazing for somebody without a brain."

Killam doesn't have a medical doctor on staff, but the clinic does have experts in traditional Chinese medicine on site. A naturopath is only a few minutes away in case of emergency, he added.

"The truth of the matter is is that if you have a problem, you phone 911 and by the time you've got them out of the chamber they're there," he said.

"The 911 boys are the best at that."

The clinic's pair of two-person chambers haven't been inspected in eight years -- they simply don't need to be, he added.

"I don't need to call them, they would come back if they thought it was necessary," he said of the inspectors who checked the units in 2002, when they were first installed.

"I get a bill every year, that must mean they've signed off on it, doesn't it?"

"No, I'm not concerned because there's nothing to be concerned about on these ones (models)."

Killam contended that mainstream medicine is closely tied to the pharmaceutical industry, therefore doctors don't want to prescribe hyperbaric oxygen for conditions that could be treated by selling medication or with surgery.

"It's actually quite sad," he said of physicians in the public system.

"They want to protect their little fiefdom, so they downgrade all this off-label stuff as being a waste of money."

On its website, Health Canada warns patients should be skeptical of "anyone who advertises or offers hyperbaric oxygen therapy to treat conditions such as multiple sclerosis, cerebral palsy, cancer, AIDS, stroke or migraine headaches" due to lack of scientific evidence.

Health Canada licenses manufacturers who wish to sell their hyperbaric oxygen chambers in Canada, but it does not keep track of them.

A spokesman for B.C.'s Health Department said there are eight private hyperbaric clinics in the province.

The chambers must meet the safety standards of their municipality and the therapy must be given -- or be supervised -- by either a qualified medical physician or naturopath, the department said.

There are around 10 public hyperbaric clinics in hospitals across Canada, all located in major cities.