Abstract: Ocular disodium cromoglycate (DSCG) 2 or 4% has been very effective in relieving the signs and symptoms associated with type I allergic eye diseases but its aqueous dispersion is unstable. An optical property characteristic of colloidal system called the Tyndall beam was found, and when a dc electric field was applied to the oculoguttae, the particles moved towards positive electrbde. The addition of electrolytes or water-miscible solvent such as alcohol to the dispersions or decrease in pH value tend to coagulate them. 4% DSCG has viscosity not much greater than of its liquid vehicle and presents low osmolality. It, therefore, appears to have colloidal properties. Solubol, a mixture of surfactants, was found to stabilize the solution, preventing flocculence or coagulation and to excert a protective action.