In 1996 there was an epidemic of bacterial meningitis in northern Nigeria. Pfizer, the world’s largest pharmaceutical company, conducted drug trials for a new antibiotic, Trovan, at a hospital in the area. Pfizer gave one hundred sick children Trovan. Pfizer gave another one hundred children Ceftriaxone, a well-established and effective antibiotic, but allegedly at a low dose to misrepresent the effectiveness of Trovan in comparison. Pfizer did not obtain the informed consent of the children or their guardians prior to administering the drugs, explain the experimental nature of the study or the risks involved, or inform them that conventional and effective treatment for bacterial meningitis was being provided for free at the same hospital. Five of the children who took Trovan and six of the children who took Ceftriaxone died, and many others were left blind, deaf, paralyzed, or brain-damaged. The children and their families (the families) (plaintiffs) sued Pfizer (defendant) under the Alien Tort Statute (ATS), claiming that Pfizer’s experiments violated international law. The district court dismissed that action for lack of subject matter jurisdiction under the ATS, and the families appealed.