A rodenticide composition is described along with a method for using the same to exterminate rodents. The composition features a mixture of a dehydrant for causing dehydration in a rodent, a water-absorbent, hygromorphic carrier for absorbing water and expanding after consumption by the rodent, and a flavoring composition. The carrier can be a source of cellulose or a non-cellulosic material. After consumption of the composition by a rodent, the dehydrant and carrier cause the rodent to experience dehydration. The rodenticide composition may also include an irritant that causes digestive stress to the rodent, which further stresses and dehydrates the rodent. Once the rodenticide composition is prepared, it may be placed in areas frequented by or infested with rodents so as to kill the rodents once they consume the composition. One or more flavorings, coloring agents, and weather resistant materials may also be added to the composition.