A method of producing fine medicament particles suitable for inhalation, particles produced by the method and apparatus suitable for carrying out the method. The method comprises contacting a stream or streams of a solution of medicament with a stream or streams of a liquid in which the medicament is insoluble in a confined chamber such that a region of intense turbulence and mixing is formed. The medicament crystallises as fine particles with minimal inclusion of solvent or anti-solvent impurities. The crystallised medicament is separated from suspension by standard techniques. Careful control of relative stream velocity, solution concentration and proportion of solution and anti-solvent in the streams ensures a uniform product.