Violetta’s salon. A revel is in full swing, and its hostess Violetta Valéry, the most beautiful courtesan in Paris, wonders how much longer her health will permit her to carry on this way. Her friend Gaston de Letourières brings her a new suitor who he says has been in love with her for a year. Her escort, the Baron Douphol, disapproves. She laughs off such devotion, but the young man, Alfredo Germont, swears that his love could cure her. She protests again: friendship, not love, is all that she can offer. She gives him the camellia from her dress and tells him to bring it back when it has wilted. Alfredo is thrilled. When the party is over, she searches her soul: amidst her frenzied life of parties and pleasures, could she possibly fall in love?

Violetta and Alfredo’s country home. Violetta has left Paris for a bucolic idyll. She and Alfredo are happier than either has ever been. She has been selling her jewels to maintain their lifestyle. A visitor is announced, who she expects will be her business agent. She is shocked to learn that he is Giorgio Germont, Alfredo’s father. He asks Violetta to leave Alfredo so that his daughter can organize a proper marriage. Violetta tells Germont how ill she is and how much she needs Alfredo, but she agrees to make the sacrifice. When Germont leaves, she writes a note to the Baron telling him she will meet him at her friend Flora’s soirée that evening. Alfredo returns to find his father waiting for him, urging him to return home to Provence. An enraged Alfredo finds the invitation to Flora’s and rushes off to Paris.

At Flora’s ball, everyone wonders what has become of Violetta and Alfredo. She enters on the arm of the Baron. Soon Alfredo appears, looking haggard. He sits down immediately to gamble, intending to win enough to buy back what Violetta has sold. As the guests go into dinner, Violetta slips away to meet Alfredo and begs him to leave. She fears the Baron will challenge him to a duel. Alfredo flings the doors wide and calls everyone in. He hurls insults at Violetta and throws his money at her: “You are all my witnesses that I have hereby paid her!” Violetta faints in Flora’s arms. Germont enters in search of his son. Only he truly understands the scene he beholds, but he cannot speak of it. Alfredo is remorse-stricken.

Violetta’s bedroom. Violetta, very weak, asks her maid Annina to open the curtains and let in the light. The streets still swell with revellers: it is the Carnival season. Violetta asks Annina to check the coin purse to see how much money remains.

The faithful Doctor Grenvil arrives; Violetta makes an effort to greet him, and asks him not to forget about her. He puts on a cheerful face with her and then whispers to Annina that her mistress has but hours to live. Violetta sends Annina out to distribute coins to the poor. She re-reads the letter she has had from Giorgio, promising that both he and Alfredo will come to ask her forgiveness for her terrible sacrifice. Annina returns, breathless with joy. Alfredo rushes into the room, takes her in his arms, and they vow to go away together to a quiet place where all will be restored. But it is too late. She struggles across the room. Germont and Doctor Grenvil have entered. She rises, painless at last … and falls.