The play opens with Medea calling on various gods to curse her husband, Jason, and his new wife. She asks the gods to kill his new wife and her family, and requests that Jason endure a suffering that is worse than death. Medea then decides that, rather than calling on the gods to mete out punishment, she will take action herself: “But why this weaving of words/This pointless whining? Will I not attack my enemies?” (I. 26-27). Medea invokes the Sun, from whom she is descended, asking him to give her magical powers to use during her quest for vengeance.

Medea discusses the violent acts she plans to carry out, explaining that such acts were common in her home region of Colchis, and will now be carried out in the city of Corinth as well. She alludes to how she committed violent acts as a young girl, and how now, as a wife and mother, her capacity for violence has only increased. Medea also references the violent beginnings of her relationship with Jason: in order to escape her homeland and begin a life with Jason, Medea killed her own brother. She believes that it is appropriate for a relationship that began with violence to also end in violence.