This paper explores the nature of causation within the framework of evidence-based practice (EBP) for health care. The aims of the paper were first to define and evaluate how causation is presently accounted for in EBP; second, to present an alternative causal account by which health care can develop in both its clinical application and its scientific research activity. The paper was premised on the idea that causation underlies medical and health care practices and impacts on the way we understand health science research and daily clinical practice. The question of what causation is should therefore be of utmost relevance for all concerned with the science, philosophy and progress of EBP. We propose that the way causation is thought of in contemporaneous health care is exposed by evidential frameworks, which categorize research methods on their epistemological strengths. It is then suggested that the current account of causation is limited in respect of both the functionality of EBP, and its inherent scientific processes. An alternative ontology of causation is provided, which has its roots in dispositionalism. Here, causes are not seen as regular events necessitating an effect, but rather phenomena that are highly complex, context-sensitive and that tend towards an effect. We see this as a better account of causation for evidence-based health care.