Thickened liquid foods are given to alleviate swallowing disorder, and their usefulness depends on the flow behavior of the liquid bolus when it is swallowed. In order to optimize the use of the bolus, its swallowing flow was simulated numerically for a pharynx. The rheological model of the bolus liquid was assumed to be a viscous power law model. The movements of the tongue and pharynx were modeled to simulate the swallowing flow. The interaction of the flow of the bolus and the movements of the pharynx were analyzed using a finite element method. In normal swallowing, the viscous liquid reduced the bolus velocity compared with the velocity of the water bolus, but the difference in the velocity because of viscosity was slight between the thickened boluses. With respect to abnormal swallowing, simulations were conducted for two kinds of disorder. (1) When the disorder was caused by dysfunction in the lift up of the throat and retroflexion of the epiglottis, the water bolus was scattered over the epiglottis and was partly aspirated. A thickened bolus of 10 cc was also aspirated from the pyriform sinuses to the larynx. A small bolus of 2 cc remained at the valleculae and then dropped down into the larynx. In contrast, a bolus of 5 cc flowed along the pyriform sinuses and was not aspirated differently from the other cases. (2) When the disorder was caused by early termination of swallowing movements, a part of the bolus remained around the epiglottis, and the return of the epiglottis induced part of the bolus to drop into the larynx. These results suggested that the pattern of the aspiration depended on the swallowing movements, and the viscosity and volume of the bolus. PRACTICAL APPLICATIONS Liquid care foods have been developed for use with swallowing disorders, and the particular viscous properties that are optimal for these foods have been studied. However, there are different types of swallowing disorder; hence, providing general guidelines for the properties of liquid care foods is difficult. The object of the study reported herein was to develop a numerical model for the simulation of the swallowing of a liquid bolus, which can be used to aid the effort to produce safe liquid care foods.