The Advertising Standards Authority (ASA) launched an investigation into the adverts published by O2HyperHealth both online and in a printed leaflet following a complaint from a council officer.
The environmental health officer spotted the Albert Street-based centre's advert while walking in the town centre and was concerned the claims risked discouraging people from seeking essential medical treatment.
Hyperbaric oxygen therapy (HBOT) has been used by the NHS for many years to treat a range of conditions, including carbon monoxide poisoning and decompression sickness.
The treatment involves breathing pure oxygen in a pressurised environment.
O2HyperHealth's website promoted HBOT by stating it "can be effective in treating a variety of acute and chronic conditions" and had been "clinically shown to... helping (sic) with depression, anxiety and stress".
In a video embedded on the website and published on O2HyperHealth's YouTube channel, on-screen text stated "pills don't always work," and added "more medication... can lead to complications."
The leaflet contained similar claims, stating HBOT could be effective in treating a variety of conditions, including "autism, asthma, migraine, stress, pain, injury, surgery, heart, bone, brain... ADHD".
When the ASA contacted O2HyperHealth during the investigation, the centre said it had not intended to characterise HBOT as a suitable replacement for essential medical treatment, but wanted to inform consumers of the potential benefits the treatment could deliver in conjunction with a healthy lifestyle.
O2HyperHealth stressed staff established whether customers had conditions which required medical treatment - or whether HBOT could potentially harm the customer - and, when necessary, told customers to seek medical advice.
On the claims made about HBOT on the website and in the leaflet, O2HyperHealth told the ASA it had taken steps to ensure each claim was supported by robust scientific evidence - and provided the ASA with web links to 74 papers published on a biomedical publication database.
But O2HyperHealth provided no detail of the relevance of the papers, while insisting many of the treatment claims stated HBOT "helped" the conditions listed in the adverts rather than replacing treatments delivered by medical professionals.
After being contacted by the ASA, O2HyperHealth removed many of the treatment claims from the adverts, but not all.
In its ruling published today (Wednesday 27 September), the ASA said rule 12.2 of the UK Code of Non-broadcast Advertising and Direct and Promotional Marketing - known as the CAP Code - stated marketers must not discourage essential treatment for which medical supervision should be sought.
The ruling added: "Evidence relating to the efficacy of a treatment for a serious medical condition was not relevant to the ASA's consideration of whether claims in an ad breached rule 12.2."
The ASA highlighted both adverts referred to depression, anxiety, asthma, autism, ADHD and infections related to diabetes - all conditions which required medical supervision.
In relation to the YouTube advert embedded on the O2HyperHealth website, the ruling noted the ad referred to "acute and chronic conditions", including "brain", "heart" and "bone" - implying the therapy could provide medical treatment for a range of neurological and heart conditions, and diseases affecting bone tissue.
The ASA said the ad gave the "overall impression the therapy could treat conditions for which medical supervision should be sought".
In upholding the complaint, the ASA ruled the adverts breached rule 12.2 of the CAP Code and ordered O2HyperHealth not to publish the adverts again and to ensure future adverts adhered to the code.
David Burrows, Rugby Borough Council chief officer for regulation and safety, said: "The council takes the safety of our communities very seriously and it's a tribute to the officer's experience and knowledge that these adverts rang alarm bells despite the council having no regulatory authority over such therapy centres.
"The CAP Code protects consumers from misleading advertising and, in cases which concern medical treatments, it's absolutely vital consumers receive accurate information in order to make an informed choice."