In a world where health advice travels faster than ever—through Instagram posts, WhatsApp forwards, and viral videos—it can be genuinely hard to know whom to trust. This is especially true when a person sounds confident, looks caring, and speaks with the easy authority of someone who claims to have answers that mainstream medicine supposedly ignores. That is why the Health Service Executive (HSE) in Ireland has issued a striking and urgent reminder: it is “crucial” to question where health information comes from. The warning follows growing concern over the upcoming appearances of Barbara O’Neill, an Australian self-described naturopath and nutritionist who has been permanently banned from providing health services in New South Wales. O’Neill is scheduled to host and speak at events across Ireland, and her presence has alarmed medical professionals in Ireland, Australia, and the UK. Their concern is not about a difference of opinion or a mild disagreement over diet tips. It is far more serious. O’Neill has been found to have told clients that cancer is a fungus that can be treated with bicarbonate of soda, and she reportedly discouraged people from undergoing chemotherapy. These are not harmless claims. For someone facing cancer, such misinformation can lead to delayed treatment, false hope, and devastating consequences. The HSE’s message, therefore, is not abstract or academic. It is a plea to every person who might one day sit in a waiting room, hear a scary diagnosis, or watch a loved one suffer: please pause, question, and verify before you believe.
To understand why health officials are so alarmed, it helps to look at the details of O’Neill’s history. In 2019, the Health Care Complaints Commission in New South Wales investigated her work and delivered a damning verdict. The commission found that she had advised clients that cancer was a fungus that could be cured with bicarbonate of soda, and that she had actively discouraged patients from receiving chemotherapy. This is not a fringe theory that simply lacks evidence; it is a claim that directly contradicts decades of scientific research and medical practice. The commission also noted that O’Neill “does not recognise that she is misleading vulnerable people (including mothers and cancer sufferers) by providing very selective information.” That phrase—“very selective information”—is important. It points to a pattern of cherry-picking facts, presenting them in a way that supports a pre-existing narrative, and ignoring the overwhelming body of evidence that says otherwise. For a person who is frightened and searching for hope, this kind of selective information can feel revolutionary and empowering. It promises a simple answer: you don’t need toxic treatments; you just need to change your diet or take a common household product. But the reality is far more complex and dangerous. Cancer is not a fungus. Bicarbonate of soda cannot cure it. And telling people to avoid chemotherapy can cost them their lives. The fact that O’Neill was banned for life from providing health services in her home state shows how seriously the Australian authorities took her conduct. Yet, because she is not practicing medicine in a traditional clinical setting, she can still travel internationally and speak to audiences as a “wellness” expert. This loophole is exactly why the HSE and medical experts are speaking out now.
A coalition of Irish, Australian, and UK medical experts has signed a letter to the venues hosting O’Neill’s events, warning that her talks will likely spread medical misinformation. Among them is Professor Mark Lawler, Professor of Digital Health and Chair in Translational Cancer Genomics at Queen’s University Belfast. His words carry the weight of someone who has spent years studying cancer and treating patients. “This person has told cancer patients to avoid chemotherapy, and that is among the reasons she has been banned for life from giving health advice in New South Wales,” he said. “I am appalled that she is able to speak to audiences on this island.” He went on to stress that her claim about cancer being a fungus that can be treated with bicarbonate of soda “has absolutely no basis in scientific fact.” But his concern goes beyond the falsehood of that specific claim. He warned that “these messages are irresponsible and dangerous, and delaying treatment will put patients at risk.” That last phrase is crucial. When someone hears a message like O’Neill’s, they may not simply ignore it; they may act on it. They may postpone a biopsy, skip an oncology appointment, or refuse a recommended course of radiation or immunotherapy. In the fight against cancer, time is often the most precious resource. A tumor that is caught early may be treatable; the same tumor, given months to grow and spread, may become far more difficult to manage. The experts who signed the letter are not trying to silence free speech. They are trying to protect vulnerable people from being exploited by false hope. They are also trying to sound the alarm to the public, in the hope that people will hear the warning before it is too late. For many of them, this is not just a professional duty; it is a moral obligation to speak up when they see harm coming.
Part of the problem, as Jennifer Feighan, CEO of the Irish Nutrition and Dietetic Institute, pointed out, is that titles like “nutritionist” are not protected by law in Ireland. This means almost anyone can use the title, regardless of their training, qualifications, or experience. Feighan explained that “more and more self-proclaimed or alternative ‘nutrition practitioners’ are emerging from informal courses.” Some of these people may be well-meaning, but good intentions are not enough when someone’s health is on the line. Others, however, may be deliberately exploiting the trust that people place in anyone who claims to be a health expert. The result is a landscape that is deeply confusing for the public. If you go to a doctor, you know they have been through years of medical school, clinical rotations, and licensing exams. If you go to a registered dietitian, you know they have completed an accredited degree and supervised practice. But if you meet someone who calls themselves a “nutritionist,” the picture is much murkier. They may be highly qualified and excellent at their job, or they may have taken a weekend course and read a few blogs. There is no way to know just by looking at their business card or website. Feighan offered a practical guide for the public: a qualified nutritionist should hold at least a BSc (Hons) or MSc in nutritional science from an accredited, evidence-based university program, and ideally should be registered with the Association for Nutrition (AfN), which maintains the UK Voluntary Register of Nutritionists (UKVRN). This is not about elitism or protecting a professional monopoly. It is about making sure that when someone gives you advice about your body, your food, or your medical treatment, they actually know what they are talking about. In an age when anyone can build a website and call themselves an expert, credentials matter more than ever.
Dr Paula Byrne, a senior research fellow and evidence synthesis methodologist at the Centre for Health Research Methodology at the University of Galway, offered advice that is both simple and empowering. “My advice is simple: ask for the evidence behind any health claim you hear and take the time to build your critical thinking skills,” she said. She pointed to free resources such as Informed Health Choices and Sense About Science’s ‘Ask for Evidence’ campaign, which are designed to help ordinary people evaluate health claims. This is a beautiful reminder that we are not powerless in the face of misinformation. We do not need to be scientists or doctors to ask basic questions: Where did this information come from? Who is making this claim? What do they have to gain? Is there independent research to back it up? What do reputable health organizations say? These questions might seem obvious, but they are often the very things that get skipped when a message is delivered with confidence and charisma. The human brain is wired to trust stories, especially stories that offer hope and certainty in uncertain times. Misinformation exploits this wiring. It dresses up in the language of healing, natural remedies, and personal empowerment, while quietly steering people away from treatments that are proven to work. Dr Byrne’s advice is to slow down and intentionally build a habit of skepticism—not the kind of skepticism that dismisses everything, but the kind that asks for evidence and listens carefully to the answer. It is a skill, and like any skill, it improves with practice. The more we ask for evidence, the more we learn to spot the difference between a genuine expert and a convincing performer. And when we do, we protect not only ourselves but also the people we love who might be influenced by the same false claims.
The HSE’s official statement reinforced this message with clarity and compassion. “Public safety is our top priority to the HSE,” the statement read. “It is crucial to question where information has come from. Take your time to check it out against reliable sources of information. This will help you decide if you can trust the advice. This advice is especially important for patients with cancer.” The HSE also described the practical steps it takes to enhance media literacy, such as making content accessible and easy to understand for all age groups, sharing accurate information through social channels, and making health experts available for media interviews and fact-checking. At the heart of this statement is a deeply human truth: information has the power to heal, but it also has the power to harm. The HSE points to its website, HSE.ie, as a trusted source of factual information, and encourages anyone with questions or concerns about their health to talk to a health professional. This is not just a bureaucratic response to a controversy; it is an invitation to build a more informed, more resilient society. In a world where misinformation can spread like wildfire, the ability to pause, question, and verify is one of the most important skills we can develop. The story of Barbara O’Neill is a cautionary tale—a reminder that confidence is not the same as competence, and that a warm smile does not guarantee good advice. But it is also a story about the power of community. Doctors, dietitians, researchers, and public health officials are speaking out together, not to silence debate, but to protect the most vulnerable among us. As the events approach, the best thing any of us can do is listen to their warning, ask the hard questions, and always, always demand the evidence. Health is too precious to be left to chance—or to charlatans.