Biopure, a company that makes blood substitutes, is suing scientist Charles Natanson for defamation after he published a critical review in the Journal of the American Medical Association. Nature magazine has condemned the lawsuit [3]. It "could have an enormous chilling effect on scientific inquiry," says Cleveland Clinic cardiologist Steve Nissen, whose controversial analyses of safety risks from the diabetes drug Avandia and the painkiller Vioxx resulted in billions of dollars in lost industry sales. Some people are saying "a plague on both houses [4]," noting that Natanson has come under criticism for "failing to disclose a conflict of interest [5] in a medical-journal article he wrote" that was critical of blood substitutes.