Barbara O'Neill, an Australian 'natural healing' guru who has claimed that cancer can be treated with baking soda, is preparing to give paid health talks across Britain and Ireland this month despite being permanently banned from providing health services in her home country, prompting fresh warnings from scientists and cancer charities.

The Australian prohibition does not prevent her from appearing at events overseas. The New South Wales Health Care Complaints Commission (HCCC) barred the 73-year-old in 2019 after finding she had made dangerous claims that were not supported by evidence.

It said she had discouraged mainstream cancer treatment, antibiotics and vaccination, and that her claims had 'real potential to have a detrimental effect on the health of individuals'.

Natural Healing Guru's UK Events and Venues

A five-day residential retreat, A Taste of Misty Mountain, is scheduled at the De Vere Cranage Estate in Cheshire in early October, with tickets priced at £700 ($929.56).

The programme includes lectures by Ms O'Neill titled 'What Really Does Cause Disease', 'The Science of Breath' and 'The Immune System', and a session by her husband, Michael, billed as 'Barbara Under Attack'.

From 13 to 15 October 2026, the Christian health group Balm of Gilead has organised a multi-day event at the City North Hotel and Conference Centre in Gormanston, Co Meath. The couple are also advertised as headlining the main stage at the Founders and Future festival at Glasgow University Union.

De Vere Cranage Estate said it hosted 'a wide range of events' for private clients and would not normally become involved in their content. Cameron MacKenzie, president of Glasgow University Union, said external events were 'in no way affiliated or endorsed' by its board and were permitted provided they complied with its terms, policies and the law.

Scientists Challenge Barbara O'Neill Bookings

Dr David Robert Grimes of Trinity College Dublin organised a letter to venues across the UK and Ireland describing Ms O'Neill as 'a leading vector of medical misinformation'.

Signatories include Orla Dolan, chief executive of Breakthrough Cancer Research, Prof Colin Doherty, head of Trinity's School of Medicine, Prof David Colquhoun, a fellow of the Royal Society, and Prof Sander van der Linden, a Cambridge psychologist.

The letter says she charges thousands of dollars for retreats and telephone consultations. Dr Grimes told the Guardian that 'medical misinformation kills'.

Prof David Elliman, a consultant at Great Ormond Street Hospital, said the science 'did not support' her suggestions and that following her advice instead of evidence-based care 'will be dangerous and result in the death of some people'.

Prof Liam Smeeth, director of the London School of Hygiene & Tropical Medicine, said he did not generally support banning speakers but called her claims 'unscientific' and the potential for harm 'great'.

Read more

Baking Soda Cancer Claims and Other Controversies

Regulators and fact-checkers have documented Ms O'Neill saying that cancer is a fungus that can be treated with bicarbonate of soda, that vaccines have caused an 'epidemic' of autism and cot death, and that pregnant women with Group B Strep do not need antibiotics.

AFP Fact Check found clips of her insisting that 'cancer loves sugar' circulating on Facebook and Instagram in Nigeria and Kenya.

Lauren Fay, a clinical nutrition manager at Inova Schar Cancer Institute in the US, said glucose fuels almost all cells, not only tumours, and that there was 'no clear evidence' diet alone could control it. Cancer Research UK has said there is no evidence that cutting out sugar can cure cancer.

Experts cited by AFP also said that diet cannot significantly alter blood pH, which is tightly regulated by the kidneys and lungs, undermining claims that 'alkaline' diets prevent tumours.

Michael O'Neill told the Guardian the HCCC ruling had 'serious legal flaws' and that his wife had never received a complaint of harm from a patient. Medical Daily could not independently verify his claims.

Read more