The effect of the addition of potato or maize on the shear-thickening behavior of semidilute solutions of maize was examined. The experiments were conducted at 25 degrees C using 90/10 weight-weight dimethyl sulfoxide (DMSO)-water as the solvent. The addition of amylose to maize amylopectin reduced and eventually eliminated the observed shear-thickening behavior of maize amylopectin. When potato amylose was combined with maize amylopectin, the shear-thickening phenomenon was observed up to a total amylose content of 10% by weight. For maize amylose, the shear-thickening behavior was eliminated at an amylose content of 5%. Maize amylose is thus more effective in inhibiting the formation of the structure formed after the shear-thickening region than potato amylose. This result indicates that the amylose obtained from potatoes interacts differently, or entangles differently, with maize amylopectin than does the amylose obtained from maize.