the present invention relates to an improved process for the purification of tiacumicin b . specifically , the invention relates to a simplified , optimised process for the purification of tiacumicin b from a fermentation broth , using chromatography techniques . in particular , the invention relates to a method for purifying tiacumicin b which comprises subjecting a liquid containing tiacumicin b to at least one hydrophobic interaction chromatography step . the process according to the invention is simpler than the processes according to the prior art , and can easily be used on a large scale for commercial production .