Research in the intensive care unit (ICU) is commonly thought to pose 'serious risk' to study participants. This perception may be at the root of a variety of impediments to the conduct of clinical trials in the ICU setting. Component analysis offers a promising approach to the ethical analysis of ICU research. Because clinical trials commonly involve a mixture of study interventions, therapeutic and nontherapeutic procedures must be analyzed separately. Therapeutic procedures must meet the requirement of clinical equipoise. Risks associated with nontherapeutic procedures must be minimized consistent with sound scientific design, and be deemed reasonable in relation to the knowledge to be gained. When research involves a vulnerable population, such as adults incapable of providing informed consent, nontherapeutic risks are limited to a minor increase over minimal risk. Understood in this way, the incremental risk posed by participation in ICU research may be minimal. This realization has important implications for review by institutional review boards of such research and for the informed consent process.