Water-soluble and water dispersible undecylenic amido propyl dimethyl hydroxyl ethoxy ethyl ammonium undecylenate compounds of formula I having anti-dandruff, preservative and sunscreen activity wherein R1, R2 are from C1-C6 carbon atoms, R3 is undecylenic acid, amino group is selected from dimethyl amino propyl amine. Personal care compositions comprising compounds of formula I ##STR00001##