National audienceIn ontologies, hierarchical relations of subsumption (is-a) and instantiation (is-instance-of) play an important role, in particular for visualizing the ontology, generally using a graph. However, these graphs become hard-to-read when the relations are numerous and complex, and when multiple inheritance is involved. This is the case in the simple example of amino-acids (20 amino-acids and 10 classes), but also in more complex applications such as the comparison of drug properties (2-10 drugs with the same indication and 10-100 classes corresponding to a common property, contraindication or adverse effect). In this paper, we present rainbow boxes, a novel visualization technique adapted to the presentation of complex and num...