When researchers in Edmonton, Canada, announced last month that a new procedure for transplanting pancreatic islet cells had freed seven adults with type I diabetes from taking insulin, the results generated a great deal of public enthusiasm. Some important caveats tended to get lost, however. One drawback is that transplant recipients would need to take immunosuppressive drugs for the rest of their lives to keep from rejecting the tissue. But more importantly, even if the benefits of the transplants outweigh the risks of the drugs, there's just not enough islet tissue to go around and there won't be anytime soon.