Formal ontology has proved to be an extremely useful tool for negotiating intended meaning, for building explicit, formal data sheets, and for the discovery of novel views on existing data structures. This paper describes an example of application of formal ontological methods to the creation of biomedical ontologies. Addressed here is the ambiguous notion of inflammation, which spans across multiple linguistic meanings, multiple layers of reality, and multiple details of granularity. We use UML class diagrams, description logics, and the DOLCE foundational ontology, augmented with the Description and Situation theory, in order to provide the representational and ontological primitives that are necessary for the development of detailed, flexible, and functional biomedical ontologies. An ontology design pattern is proposed as a modelling template for inflammations.