Abstract: A hydrophobically modified anionic cellulose ether obtainable by a process comprising reacting an alkali metal cellulose with at least three alkylating reagents A, B, and C. Reagent A is selected from the group of haloacetic acids, alkali metal haloacetates, alkali metal vinyl sulfonates, and vinyl sulfonic acid. Reagent B has the formula R1—(OCH2CH(R2))n—P, wherein R1 represents a C2-C7 group, R2 is hydrogen or a methyl group, n is 0-2, and P represents a glycidyl ether group, a 3-halo-2-hydroxypropyl ether group, a 1,2-epoxy group, or a halide, and reagent C has the formula R3—(OCH2CH(R2))m—P, wherein R3 represents a C8-C30 group, m is 0-10, and R2 and P have the meaning as described above.