To participate in health research, there is a need for well-administered informed consent. Understanding of informed consent, especially in international health research, is influenced by the participants' understanding of information and the meaning attached to the information communicated to them regarding the purpose and procedure of the research. Incorrect information and the power differential between researcher and participants may lead to participants becoming victims of harmful research procedures. Meningitis epidemics in Kano in early 1996 led to a response from drug companies, especially Pfizer, as well as humanitarian workers from Médecins Sans Frontiers, which resulted in an unethical trial. Pfizer's drug trial during the epidemics has left a lasting controversy, which has yet to be resolved. This paper examines the key issues surrounding the controversy, discusses the context of informed decision-making, the ethical issues and implications of the incident, and concludes with some recommendations. Relevant texts, journals, Internet materials, newspaper articles and documentary materials on the conduct of the Pfizer's Trovan trial have been consulted. Four types of action (act intuitively, act rationally, act ignorantly, and act contextually - based on information provided) are identified as possible options for decision making. Participants most likely acted in ignorance due to poor understanding of the information contained in the verbal informed consent administered, thereby raising ethical issues. It is concluded that health research ethics committees have an important role to play nationally and locally in overseeing research, and in avoiding future occurrences.