A method for the manufacture of carboxyalkylinulin is disclosed comprising preparing an aqueous medium containing dispersed therein a halogenoalkylcarboxylate, adding to the carboxylate containing medium, under substantially neutral pH conditions, an inulin followed by heating this mixture to a temperature in the range of from 60.degree. C. to 90.degree. C. and proceeding with the reaction at alkaline conditions, pH 8-12, while simultaneously adding additional halogenoalkylcarboxylate and alkalihydroxide. The carboxyalkylinulin so formed is recovered in a manner known per se.