According to Aristotle in Poetics, a tragic hero in an ancient Greek tragic play suffers from a tragic flaw (hamartia) that causes their tragic downfall. The tragic hero also undergoes a reversal of fortune (peripeteia) and makes a critical discovery about themselves or their situation (anagnorisis).

Jason's tragic flaw, which he shares with many ancient Greek tragic heroes, is his excessive pride (hubris). This hubris is clearly evident in his attitude towards women.

JASON. Not thine own self would say it, couldst thou still
One hour thy jealous flesh.—'Tis ever so!
Who looks for more in women? When the flow
Of love runs plain, why, all the world is fair:
But, once there fall some ill chance anywhere
To baulk that thirst, down in swift hate are trod
Men's dearest aims and noblest. Would to God
We mortals by some other seed could raise
Our fruits, and no blind women block our ways!
Then had there been no curse to wreck mankind.

Jason's hubris and his misogyny permit him to commit adultery and to indulge his ambition, which drives him to abandon Medea and their children and to marry Glauce, the daughter of Creon, the King of Corinth. Jason's actions, motivated by his hubris, inevitably lead to his tragic fall.

Jason's reversal of fortune (peripeteia) occurs when Medea fulfills her own curse against those who have wronged her, and she kills Glauce, Jason's new wife, Glauce's father, the King of Corinth, and her own children.

Jason's anagnorisis is the moment that the realizes that due to his own hubris and his own actions, he now has no family and no future.

MEDEA.Thy broken vows, thy friends beguiled
Have shut for thee the ears of God.

Jason's fate also provides the audience with a catharsis, an essential part of a Greek tragedy, which is the release of the emotions of pity and fear that the audience feels for Jason's inevitable downfall.