Catharisis refers to a purgation or purification of the emotions of the audience by art. According to Aristotle, it is applied to a tragedy which can produce in the audience purgation of fear and pity and then gives a heightened understanding of the ways of gods and men. In both plays, Catharisis allows the dramatists to raise the prevailing themes as well as fully express their perceptions toward the society. In Euripides’ Medea, the woman with magic was taken back to a civilized society. However, Medea emotionally suffered as her husband, Jason, betrayed her. Since she is the woman, the outcast, and the foreigner, in a new environment, barely did she own her right to voice for herself. Having nowhere to turn to, she had a quarrel with Jason and planned her plot against him to revenge. She decided to murder the princess of Corinth and their sons, and eventually she succeeded, leaving the play ending in disorder. Now, the audience would not feel frightened because of the employment of Catharisis. Euripides projects the inequality of sex and attacks the Greek masculinity, but unlike Homer’s epic, the unspeakable violence attributes to the long-term oppression and pent-up. In Oedipus the King, Oedipus determined to leave his country in prevention of the fulfillment of the oracle. He was said to murder his own father and marry his own mother. Even so, he had an argument on his way of wandering, lost his temper, and killed an old man he met in a rage. The old man happens to be his father. After the incident, Oedipus managed to defeat the monster, Syphnix, by answering her puzzle. Thus, Oedipus became the legitimate king and marry the queen. Audience are abke ti fully participate in process of his downfall. The playwright, Sophocles, intends to address the playing fate as well as their harmartia (tragic flaw) when Jocasta attempted to comfort Oedipus that oracle could be sometimes misinterpreted. Her ignorance to the oracle leads him to realize his identity. Likewise, Oedipus has a free will. He should be responsible for his deeds. Throughout the entire play, audience can attach the function of catharisis to the main theme: sight. It expounds that what we see might not be absolutely self-evident. There could be something beyond our capacity of understanding. In the ancient Greek theater, many devices are used in help of enabling the dramatists to deliver messages. Catharisis plays a critical role to Greek tragedy because it has a therapeutic effect on the audience. In other words, it purifies the disquieting the emotions of our daily life.