We have found that presumed cyclo-oxygenase inhibitors convert anaphylaxis from a serious disorder into a catastrophic disorder. Yet some of these drugs, in higher doses, prevent anaphylaxis. The lower doses completely inhibit cyclo-oxygenase, and it can be assumed that the higher doses do as well. Hence it appears that products of the cyclo-oxygenase are not of critical importance in the pathogenesis of anaphylaxis. We propose to help define the effects of high dose "cyclo-oxygenase inhibitors" that contribute to the amelioration of anaphylaxis.