The present invention relates to an active crystalline material, especially an active multicomponent crystalline material such as a salt or a cocrystal, which may be made by dispersing precursor components of the active crystalline material in a liquid medium which comprises an anti-solvent, maintaining the dispersion for a period during which the active crystalline material is formed, and, during said period, exposing the dispersion to a solvent, which solvent being present in the liquid medium in a minor proportion by weight thereof.