Justice Rehnquist delivered the opinion of the Court.
This case presents the question of the extent to which a decision of an administrative agency to exercise its "discretion" not to undertake certain enforcement actions is subject to judicial review under the Administrative Procedure Act, 5 U. S. C. § 501 et seq. (APA). Respondents are several prison inmates convicted of capital offenses and sentenced to death by lethal injection of drugs. They petitioned the Food and Drug Administration (FDA), alleging that under the circumstances the use of these drugs for capital punishment violated the Federal Food, Drug, and Cosmetic Act, 52 Stat. 1040, as amended, 21 U. S. C. § 301 et seq. (FDCA), and requesting that the FDA take various enforcement actions to prevent these violations. The FDA refused their request. We review here a decision of the Court of Appeals for the District of Columbia Circuit, which held the FDA's refusal to take enforcement actions both reviewable and an abuse of discretion, and remanded the case with directions that the agency be required "to fulfill its statutory function." 231 U. S. App. D. C. 136, 153, 718 F. 2d 1174, 1191 (1983).
I
Respondents have been sentenced to death by lethal injection of drugs under the laws of the States of Oklahoma and Texas. Those States, and several others, have recently adopted this method for carrying out the capital sentence. Respondents first petitioned the FDA, claiming that the drugs used by the States for this purpose, although approved by the FDA for the medical purposes stated on their labels, were not approved for use in human executions. They alleged that the drugs had not been tested for the purpose for which they were to be used, and that, given that the drugs would likely be administered by untrained personnel, it was also likely that the drugs would not induce the quick and painless death intended. They urged that use of these drugs for human execution was the "unapproved use of an approved drug" and
