Multiple interventions are implemented to save the lives of a critically ill patients. The therapeutic value of most of these interventions remains untested. Enrollment of patients in the intensive care unit into multiple studies could improve the efficiency of testing interventions in the intensive care unit. Unfortunately, enrollment of intensive care unit patients into multiple studies is often discouraged. If the same patient is enrolled into more than one study, there is a risk that interactions between interventions could lead to false conclusions. In addition, there is a belief that the families of critically ill patients might feel overly stressed if they are repeatedly approached for consent. This article provides a rationale for enrolling intensive care unit patients into multiple clinical trials. Factorial designs are efficient, but their inherent limitations must be noted. The little evidence that is available shows that most patients would enroll in multiple studies and do not feel overly stressed by participating in more than one study. Modifications to subject consent, data collection, and data analysis for coenrollment could facilitate it. In conclusion, more vigorous promotion of thoughtful coenrollment policies could increase the efficiency of critical care research.