There is disclosed a method for treating a source of azadirachtin: (a) dissolving said sample in an organic polar solvent; (b) combining the solution of step (a) with an organic non-polar solvent to form a single phase containing the said solvents and dissolved sample; (c) treating said single phase of step (b) with an aqueous salt solution to form an aqueous phase and a phase containing the organic non-polar solvent; and (d) recovering one or other or both of the aqueous phase and the phase containing the organic polar solvent.