Process for the recovery of a macrolide in substantially pure form comprising: a) treatment of an impure or crude macrolide with water immiscible solvent, b) optional concentration of the mixture, c) treatment with ammonia gas to phase out impurities, d) separation of impurities, d) optional concentration of the phase containing the macrolide, f) loading on silica gel chromatography, optionally reversed phase or pretreated with silver, and elution of the macrolide, g) affording the macrolide in substantially pure form, h) optional repetition of step f) and g) to afford the macrolide in substantially pure form. The macrolide is preferably tacrolimus, immunomycin or sirolimus.