The problem of animal suffering considers whether God would allow millions of years of animal pain, disease, and death. Philosophers who debate this issue often assume that pain and suffering are evils a loving God would not allow without good reason. Moreover, a considerable amount of the debate regarding the problem of animal suffering involves whether animals are capable of experiencing pain and suffering. But this raises the question of whether pain and suffering are intrinsically evil. In this essay I explore the nature of pain and suffering from a Thomistic perspective. First I briefly explain how the intrinsic values of pain and suffering are crucial regarding the problem of evil and the problem of animal suffering in particular. Next I explain the Thomistic concepts of pain and suffering and show that they do not contradict their contemporary philosophical and scientific counterparts. Afterward I determine whether pain and suffering are intrinsically evil experiences that an all-good God should refrain from causing. I conclude that pain and suffering are not intrinsically evil and that the problem of animal suffering is not a problem in addition to the problem of natural evil.