The relation between the notions of (medical) invasiveness and (actual or potential) harm has not been systematically discussed nor theoretically grounded, despite its importance to clinical-ethical practice. This paper aims to clarify the notion of invasiveness beyond the traditional notion of invasiveness as breaking skin or inserting mechanical objects into the body. The traditional notion of invasiveness is challenged by counterexamples. Three approaches to the notion of disorder applied here are: deviation from what is common; deviation from what is considered (...) ideal; and disruption of self-organization. Assuming that more extreme measures are related to more harm, all three approaches to the notion of disorder suggest that invasiveness is proportional if not identical to harm, and show no clear relation to the traditional notion of invasiveness. In conclusion, the notion of invasiveness may best be eliminated from medical terminology, replacing it with a detailed understanding of the notion of harm. (shrink)