A cellulose ether which has from 4,000 to 10,000 anhydroglucose repeat units and is substituted with (a) on the average from 0.0003 to 0.08 moles, per mole of anhydroglucose unit, of a substituent comprising an alkyl or arylalkyl group having from 8 to 24 carbon atoms and (b) a substituent having the formula II wherein R5, R6 and R7 each independently are &mdash；CH3 or &mdash；C2H5, R8 is &mdash；CH2&mdash；CHOH&mdash；CH2&mdash； or &mdash；CH2CH2, Az&minus； is an anion, and z is 1, 2 or 3 is useful in hair and skin care compositions.
