The US Food and Drug Administration (FDA) said Thursday it was concerned about claims that tout hyperbaric oxygen therapy, which involves breathing oxygen in a pressurized chamber, as the kind of universal treatment for diseases such as cancer, autism and diabetes.

"No, hyperbaric oxygen therapy has not been clinically proven to cure or be effective in the treatment of cancer, autism, or diabetes," the FDA said in a statement.

"But do a quick search on the Internet, and you'll see all kinds of claims for these and other diseases for which the device has not been cleared or approved by FDA," it said.

The FDA said it has cleared hyperbaric chambers for certain medical uses, such as treating decompression sickness suffered by divers, but some claims made by treatment centers using hyperbaric oxygen therapy may give consumers a wrong impression that could ultimately endanger their health.

"Patients may incorrectly believe that these devices have been proven safe and effective for uses not cleared by FDA, which may cause them to delay or forgo proven medical therapies," said Nayan Patel, a biomedical engineer in FDA's Anesthesiology Devices Branch. "In doing so, they may experience a lack of improvement and/or worsening of their existing condition(s)."

The FDA said, the safety and effectiveness of hyperbaric oxygen therapy have not been established for these diseases and conditions, including: AIDS/HIV, Alzheimer's disease, asthma, Bell 's palsy, brain injury, cerebral palsy, depression, heart disease, hepatitis, migraine, multiple sclerosis, Parkinson's disease, spinal cord injury, sport's injury and stroke.

Patel said that the FDA has received 27 complaints from consumers and health care professionals over the past three years about treatment centers promoting the hyperbaric chamber for uses not cleared by the agency.

Hyperbaric oxygen therapy involves breathing oxygen in a pressurized chamber in which the atmospheric pressure is raised up to three times higher than normal. Under these conditions, the lungs can gather up to three times more oxygen than would be possible breathing oxygen at normal air pressure.

Hyperbaric oxygen therapy increases the amount of oxygen dissolved in the blood, and an increase in blood oxygen may improve oxygen delivery for vital tissue function to help fight infection or minimize injury, the FDA said.

Patients receiving hyperbaric oxygen therapy, however, are at risk of suffering an injury that can be mild, such as sinus pain, ear pressure, painful joints, or serious, such as paralysis, air embolism. Since hyperbaric chambers are oxygen rich environments, there is also a risk of fire.

"If you're considering using HBOT (hyperbaric oxygen therapy), it's essential that you first discuss all possible options with your health care professional," Patel said.