Abstract: A process is provided for making alkylated galactomannans comprising reacting a galactomannan in the presence of sodium hydroxide, water, and an alkyl halide to form a reaction mass under pressure and at temperatures greater than 50.degree. C. in amounts and for a time sufficient to achieve a degree of substitution greater than 2.4. Organic volatiles from the reaction mass are stripped and the reaction mass is then washed in water at temperatures high enough to prevent dissolution or agglomeration of the alkylated galactomannan. This washed product is then dried and pulverized to suitable particle size. This product is useful in applications requiring thickening and rheology modification of formulations containing organic solvents or formation of coatings/film from organic solvents. The products are also useful in pharmaceutical applications.