An aqueous composition useful for producing capsules shells comprises a) at least one dispersed esterified cellulose ether comprising (i) groups of the formula —C(O)—R—COOA or (ii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and b) from 0.05 to 20 percent of at least one salt of a fatty acid, based on the weight of the dispersed esterified cellulose ether, wherein the median particle size, d50, of the dispersed esterified cellulose ether particles is up to 7 micrometers, such median particle size (d50) being the size at which 50 mass percent of the particles have a smaller equivalent diameter and 50 mass percent have a larger equivalent diameter.