The natural compound curcumin was incorporated into various micellar systems in order to improve the water solubility and the hydrolytic and photochemical stability. The presence of micellar structures resulted in an increase in water solubility at pH 5 by a factor of at least 10(5). The hydrolytic stability of curcumin under alkaline conditions was strongly improved by incorporation into micelles while the photodecomposition rate was increased compared to curcumin in hydrogen bonding organic solvents or aqueous solutions. The ability of curcumin to act as a photosensitizer was dependent on the type of micelles and pH of the medium.