L'elisir d'amore (The Elixir of Love) is a melodramma giocoso (opera buffa) in two acts by the Italian composer Gaetano Donizetti. Felice Romani wrote the Italian libretto, after Eugène Scribe's libretto for Daniel Auber's Le philtre [es] (1831). The opera premiered on 12 May 1832 at the Teatro della Canobbiana in Milan.

To make a safe escape, Dulcamara tells Nemorino the potion needs 24 hours to take effect – by which time, the doctor will be long gone. Nemorino drinks the potion in haste in order to watch the effect the following day. Emboldened by the "elixir" (in fact, drunk), Nemorino feigns indifference when he encounters Adina, as he expects that the elixir will facilitate his conquest of Adina the next day. She becomes increasingly annoyed; perhaps she has feelings for Nemorino after all? Belcore returns and proposes marriage to Adina. Still riled by Nemorino and wishing to give him a lesson, Adina falsely promises to marry Belcore in six days' time. Yet, Nemorino only laughs in response: such confidence is sustained in the belief in the magic potion. However, when Belcore learns that his regiment must leave the next morning, Adina promises to marry him before his departure. This of course panics Nemorino, who cries out for Dr. Dulcamara to come to his aid. Adina, meanwhile, invites everyone to the wedding.

After the two men have left, Giannetta gossips with the women of the village. Swearing them all to secrecy, she reveals that Nemorino's uncle has just died and left his nephew a large fortune. However, neither Nemorino nor Adina is yet aware of this. Nemorino enters, having spent his military signing bonus on – and consumed – a large amount of the fake elixir from Dr. Dulcamara. Hoping to share his fortune, the women approach Nemorino with overly friendly greetings. So out of character is this that Nemorino takes it as proof of the elixir's efficacy. Adina sees Nemorino with the women, is rattled by his newfound popularity, and asks Dr. Dulcamara for an explanation. Unaware that Adina is the object of Nemorino's affection, Dulcamara explains that Nemorino spent his last penny on the elixir and joined the army for money to get more, so desperate was he to win the love of some unnamed cruel beauty. Adina immediately recognises Nemorino's sincerity, regrets her behaviour and realises that she has loved Nemorino all along. Although Dulcamara seizes the opportunity to try to sell her some of his potion to win back Nemorino, Adina declares that she has full confidence in her own powers of attraction.

Nemorino appears alone, pensive, reflecting on a tear he saw in Adina's eye when he was ignoring her earlier. Solely based on that, he convinces himself that Adina loves him. She enters and asks why he has chosen to join the army and leave the village. When Nemorino explains that he was seeking a better life, Adina responds that he is loved and that she has purchased back his military contract from Sergeant Belcore. She offers the cancelled contract to Nemorino and reassures him that, if he stays, he will be happy. As he takes the contract, Adina turns to leave. Nemorino believes she is abandoning him and flies into a desperate fit, vowing that if he is not loved he might as well go off and die a soldier. Deeply moved by his fidelity, Adina finally declares that she will love Nemorino forever. Nemorino is ecstatic. Adina begs him to forgive her, which he does with a kiss. Belcore returns to see Nemorino and Adina in an embrace. When Adina explains that she loves Nemorino, the Sergeant takes the news in stride, noting that there are plenty of other women in the world. Adina and Nemorino learn about the inheritance from his uncle. Dulcamara returns and boasts of the success of his elixir: Nemorino is now not only loved but also rich. Dulcamara exults in the boost this will bring to the sales of his product. As Dulcamara prepares to leave, everyone queues up to buy the elixir and to hail Dulcamara as a great physician.