To investigate the flow properties of neat and CaCO₃-filled aqueous solutions of polyvinylalcohol(PVA) and hydroxyethylcellulose(HEC), the viscosity of the solutions was measured by a rotational type viscometer. The aqueous solution of HEC showed a typical pseudoplasticity. while PVA exhibited a near Newtonian flow behavior. When CaCO₃ was suspended in these two aqueous solutions, HEC showed more noticeable yield behavior than PVA. In addition, filler effect on the yield stress, evaluated by the Casson plot, was more pronounced with HEC suspensions than with PVA suspensions.