Four adducts were prepared by polymerizing acrylic acid (AA) in presence of either a pyrodextrin (D) or gum Arabic (GA), and termed as PAA/D-1, PAA/D-2, PAA/GA(1), and PAA/GA(2). These adducts were utilized as thickeners in reactive printing of cotton fabric in comparison with Na-Alginate. Printing was carried out at different conditions including: NaHCO3 concentration (0-40 g/K), urea concentration (0-200 g/k), steaming temperature (100-130 degrees C) and time (5-35 min). At optimal NaHCO3 concentration (30 g/K) the depth of shade of the prints, expressed as K/S values, depended on the nature of the thickener used, and followed the descending order PAA/D2 > PAA/GA, > Na-Alginate >> PAA/D-1 >= PAA/GA(2). Accordingly, PAA/D-1 and PAA/GA(2) were omitted in subsequent trials. Optimal printing conditions were found to be NaHCO3 concentration (30 g/K), urea concentration (100 g/k), steaming temperature (110 degrees C), and time (15 min). The apparent viscosity of a printing paste, as well as both of K/S value and fastness properties of a print were governed by the nature of the reactive dye and type of thickener. Storing of a printing paste up to 7 days resulted in a decrease in its apparent viscosity along with a slight reduction in K/S value and a little variation in some fastness properties of prints. (c) 2006 Wiley Periodicals, Inc.