Interacting selectively and non-covalently with a DH (Dbl homology) domain of a protein. The DH domain contains three structurally conserved regions separated by more variable regions. It is composed of 11 alpha helices that are folded into a flattened, elongated alpha-helix bundle in which two of the three conserved regions, conserved region 1 (CR1) and conserved region 3 (CR3), are exposed near the centre of one surface. CR1 and CR3, together with a part of alpha-6 and the DH/PH (pleckstrin homology) junction site, constitute the Rho GTPase interacting pocket.