Starch with its hydroxyiic groups can excite fluorescein. This dye, red when solid and fluorescing when hydrated in aqueous solution exhibited a yellow fluorescence when sorbed on starch. Comparison of the properties of starch – KI_S, starch – fluoresceine, and starch – KI_S – fluoresceine complexes led to the conclusion that fluorescein formed surface complexes and also entered the amylose helix.