Infill walls in frame, often stiff and brittle, are able to significantly influence the seismic behaviour of the structure, invalidating many design basic assumptions based on the behaviour of the bare frame. Nevertheless, in hot climate regions, it is not possible to think of buildings without massive infills, due to the requirement of controlling energy consumption for residential climate control. To overcome this problem, the possibility of assembly ductile infills was investigated. The basic idea was to use weakness as a resource, pursued both through the choice of materials and the proposal of a simple building technique. Particular attention was devoted to adobe (earthen bricks) infills, to take advantage of its intrinsic weakness, often unacceptable for other applications. The paper presents the main results of an experimental campaign comparing the performances of hollow fired clay bricks and adobe as building material for the infill walls.