In the history of philosophy, the use of contrasts and simplifications to aid understanding often makes some people ignore details and distort the arguments of certain thinkers. There has been misconception that Stoic philosophy is an unrealistic idea that imposes extreme self-denial and ignores emotions. Even in the case of Seneca's anger theory, his claim to thoroughly block anger can be misunderstood as an unrealistic method combined with the extreme impression of the Stoics. In this article, I try to reveal the fact that Seneca's anger theory is more realistic than those of Aristotle or Philodemus in terms of philosophical practice. For this, in section 2, I analyze the definition, cause, stage of occurrence, and attributes of anger, which are theoretical aspects of Seneca's anger theory. Anger is defined as “the desire to take revenge for unjustly done injustice” and classified as a passion or vice. The cause of anger is the idea that someone has suffered injustice and that he is not at fault and that he voluntarily agrees to it. Anger consists of three stages: the stage of entry into the mind, the stage that arises or is eliminated through deliberation, and the stage of out-of-control. Anger has the properties of being out of control, harmless, congenital and acquired of causes, and dependence on consent. In Section 3, as a practical aspect of Seneca's anger theory, methods for preventing anger, treatment, and coping with other people's anger are analyzed. As preventive methods, fostering good character through encouragement and admonition, increasing self-esteem, anticipation and reflection, and environmental maintenance are suggested. As treatment methods, probation, initial suppression and logical rebuttal are suggested. And as a method for coping with anger of others, initial waiting, later inducing shame and fear strategy is suggested. In section 4, I introduce Aristotle’s and Philodemus’ theories of anger and show the superiority of Seneca's theory of anger to them. In comparison with Aristotle, who defined anger as a desire for revenge for unjustified disregard, and who pursued a kind of moderation of mildness, and Philodemus, who divided anger into empty anger and natural anger, Seneca, who rearranged the concept of anger and held the realistic uncontrollability of anger, has more appeal. Also, compared with their ideal and broad concepts of anger, Seneca's realistic and narrow concept of anger is superior in four aspects: clear targeting, realistic control, specific methodologies, and emphasis on self-esteem. I expect that this article will be a basis for the development of philosophical practice anger therapy based on Seneca's anger theory in the future.