There is a growing trend toward evidence-based medicine, in which patient-oriented data are valued more highly than disease-oriented evidence (DOEs). In the vernacular of evidence-based medicine, the old DOEs are slowly being replaced by POEMs (patient-oriented evidence that matters). Unfortunately, POEMs do not yet exist to meet every family-practice need. When there are no POEMs to determine an appropriate therapeutic choice, another decision-making method must be used. This method includes liberal use of DOEs combined with thoughtful use of causal pathways to provide preliminary direction. This article applies that method to an example from the growing basic science surrounding endothelial functioning.