Jocasta is the wife and mother of Oedipus. In her first scene, she is extremely upset when Creon and Oedipus are arguing. She shames them, reminding them that the country is in a state of suffering from the plague that resides on the country. She stops the argument.
At first, Jocasta is convinced that Oedipus could not have been King Laius's murderer. She claims that highwaymen killed King Laius:
She assures Oedipus that the oracle proclaiming Laius's murder by his own son was false, since Laius was killed by highwaymen, and his son had been left "to die on a lonely mountainside."
With that being said, Oedipus begins thinking about the man he killed on the highway. He remembers killing a man on the highway. They send for the messenger who witnessed King Laius's murder. He begins sharing the details.
While Oedipus is adding up the details, Jocasta is also filling in the blanks. When she realizes that Oedipus is her son and husband, she cannot bear to think upon it.
Jocasta tries to stop the messenger form stating what she has just figured out:
Later in the same scene she tries to stop him from questioning the messenger regarding his true father: "May you never learn who you are!"
She is realizing that Oedipus is indeed her son. She cannot bear to live with the fact. She goes to her room and hangs herself.
In her final speech she calls Oedipus "miserable'' and says she will have no other name for him. Towards the end of the play a second messenger reports that she has hanged herself, giving a moving account of her wailing and physical expressions of grief during her last moments.