A simple and efficient method for the separation of the three phenolic diketones, curcumin 1, demethoxycurcumin 2, and bis-demethoxycurcumin 3, isolated from the rhizomes of Curcuma longa has been developed. The method is of general applicability for the separation of compounds containing acidic and chelating groups and is amenable to large scale separations. The curcumins 1-3 show moderate activity against Plasmodium falciparum (IC₅₀: 3.5, 4.2 and 3.0 μg/ml) and Leishmania major (IC₅₀: 7.8, 14.1 and 21.5 μg/ml) respectively.