When stem-cell clinics are asked for documentation about the treatments they offer, some are quick to produce letters from lawyers instead. In the face of legal threats from clinics, the Inter­national Society for Stem Cell Research (ISSCR) has suspended a service intended to help patients wade through claims about therapies. It is now pondering its next move.

For stem-cell researchers, the worldwide proliferation of clinics offering regenerative medicine is frustrating. Many of the treatments such clinics offer — injecting a patient's own stem cells back into his or her body in a bid to treat conditions ranging from Parkinson's disease to spinal-cord injuries — are at best a waste of money, and at worst dangerous. "There's real potential to damage the legitimacy of the field," says Timothy Caulfield, who studies health law and policy at the University of Alberta in Edmonton, Canada.

There’s real potential to damage the legitimacy of the field. ,

Last June, the ISSCR, which is based in Deerfield, Illinois, launched its 'Submit a Clinic' website in an effort to educate patients. "Have you seen an advertisement for a stem cell clinic or other stem cell treatment provider and want to know more about it?" the site asked, and invited users to submit the names of centres. The ISSCR offered to find out whether providers had medical-ethics committees and were overseen by a regulatory agency such as the US Food and Drug Administration (FDA) or the European Medicines Agency. The answers were to be posted on the society's website.

But some of the initial inquiries drew letters from lawyers, challenging the society's authority to question the clinics. Elaine Fuchs, a stem-cell researcher at Rockefeller University in New York and former president of the ISSCR, says that the society sought legal advice and was assured that it stood on firm ground. Even so, she says, everyone recognized that lawsuits would quickly drain the society's limited resources.

In February, the ISSCR shelved the project. At the society's annual meeting in Toronto, Canada, this month, Irving Weissman, a stem-cell researcher at Stanford University in California, turned to the audience for advice. "What should we do?" he asked. "Should we risk litigation?" The audience could not come to a consensus, and the programme is still on hold.

Some researchers worry that patients will now turn for guidance to the International Cellular Medicine Society (ICMS) in Salem, Oregon — an organization of patients and physicians, some of whom have close ties to the regenerative-medicine industry. The ICMS, which offers accreditation to stem-cell clinics, was co-founded by the medical director of Regenerative Sciences, a clinic based in Broomfield, Colorado. Last August, the FDA requested a federal injunction against Regenerative Sciences for failing to adhere to proper manufacturing standards (see Nature 466, 909; 2010).

Clinics operate without controls in many countries. In May, Germany shut down a notorious stem-cell clinic linked to the death of a toddler and the near-death of a ten-year-old boy, but other centres offering unproven treatments remain open around the world. In the United States, clinics have tended to escape regulation. The FDA steps in only if the treatment fits certain criteria — for instance, if the agency determines that the stem cells are significantly manipulated after being extracted, or if they are being used in a patient other than the donor.

Fuchs emphasizes that the ISSCR still has options for educating patients and policy-makers about the risks of unproven treatments. Its website lists questions that patients should ask when evaluating a clinic, and the society is discussing ways to educate the media, which sometimes gives uncritical coverage to such clinics (A. Zarzeczny et al. Nature Biotechnol. 28, 1243–1246; 2010). It already has plans to target primary-care physicians, says Caulfield; the ISSCR hopes to publish an article on stem-cell clinics in Canadian Family Physician, a medical journal sent to every general practitioner in Canada, he notes.

In the meantime, stem-cell researchers face a steady stream of e-mails seeking advice about clinics. Caulfield responds to these inquiries cautiously, mindful of the threat of litigation. "And I'm a little bit cowardly when I write articles about this," he says. "I don't mention the clinics by name."