Recent discussions of the doctrine of double effect have contained improved versions of the doctrine not subject to some of the difficulties of earlier versions. There is no longer one doctrine of double effect. This essay evaluates four versions of the doctrine: two formulations of the traditional Catholic doctrine, Joseph Boyle's revision of that doctrine, and Warren Quinn's version of the doctrine. I conclude that all of these versions are flawed. Keywords: double effect, intention, Joseph Boyle, medical ethics, Warren Quinn CiteULike Connotea Del.icio.us What's this?