Donizetti was one of the most prolific composers of his age. Apart from his emotionally rich tragedy Lucia di Lammermoor, he was primarily known for his comic operas. With a kind and indulgent smile, L'elisir d'amore broaches a question that is important to all of us: what is it that makes two people fall in love with each other? For lack of better options, the poor peasant lad Nemorino puts his faith in the love potion concocted by the charlatan “doctor” Dulcamara, while his adored Adina gradually realises that it is not the power of money, but the strength of commitment that is able to sustain a relationship. As the two youngsters fall for each other and Dulcamara stuffs his wallet, the audience gets to once again hear the – ageless – bravura arias and duets, secure in the anticipation of a happy ending.
The peasant Nemorino is hopelessly in love with the wealthy young lass Adina, who as the curtain opens is reading the tale of Tristan and Isolde out loud to the villagers. Everyone marvels at the effect of the love potion in the story.
Arriving in the village in the meantime is the local guard, led by Belcore. The corporal immediately starts to woo Adina, and even asks for the girl's hand in marriage. Seeing Belcore's self-assured courtship and boasting, Nemorino is filled with despair. Although Adina cleverly eludes the marriage proposal, Nemorinos's situation is not improved: he is so clumsy and awkward, all he would be able to do is throw himself at her feet so that she will take pity on his sorrow.
Adina abruptly ends her conversation with Belcore. The villagers disperse, but Nemorina hurries after Adina. Long since bored of his sighing and obsessive love, the girl advises him to instead to go to the town, where his ailing uncle lives. Nemorino, however, is unable to part from her. It doesn't matter to him if his well-to-do uncle leaves his money to someone else: he'd prefer poverty to life without Adina. Adina tells him frankly that her heart is not capable of loyalty. Despite the warning, Nemorina is unable to give up on her.
In the meantime, an unknown gentleman arrives in the village on a golden carriage. Doctor Dulcamara offers the key to a happy life, as the medicine he has invented is good against every trouble.
Nemorino asks the doctor for a potion. Laughing up his sleeve at the villagers for being so gullible, he provides Nemorino with a vial, along with a warning not to breathe a word about it to anyone, since it is against the law to sell such substances. The lad immediately gulps it down, convinced that all he has to do is wait one day before everything comes together for him, since Dulcamara promised him that the potion would take that long to take effect – giving himself enough time to escape. Marvelling at Nemorino's cheerfulness, Adina is visibly relieved to see that he has given up on her.
Belcore returns. In order to annoy Nemorina, Adina assures the corporal that all he has to do is wait for six days, and she will give him her heart. The sight of Belcore's triumphant victory only makes Nemorino laugh, so certain is he that the potion will achieve the desire effect the next day.
Having received orders to leave the village the next days, Belcore asks that they announce the engagement that evening. The girl consents. Nemorino begs Adina not to agree to marry Belcore that night, for she will regret her decision if she does not wait until the morning.
Enraged, Belcore turns on the lad. Although Adina defends him, she too is plotting revenge on Nemorino. She tells Belcore that they should hurry to the notary and announce the engagement that evening.
Adina and Belcore are celebrating their engagement. Adina is still only thinking about how to vex Nemorino. The notary arrives, but Nemorino is not present for Adina's revenge, meaning that her entire plan to get back at him has fallen through.
His heart about to break, Nemorino runs into Dulcamara, who has been invited to attend the engagement party. The lad asks him for some kind of drug that will make Adina fall in love with him right away. Concealing his derision, the doctor offers Nemorino yet another substance – and a double dosage of it, at that. But since Nemorino has no money, Dulcamara ends up refusing to give him anything.
Meanwhile, Adina is holding up the engagement party.
Running into Belcore, Nemorino tells him he has no money. The corporal suggests that he enlist as a soldier, which will immediately yield him twenty gold scudi. After hesitating briefly, Nemorino signs the recruitment contract and rushes off to Dulcamara with the money.
Meanwhile, news has been spreading secretly that Nemorino's rich uncle has died that night, leaving all his money and land to his nephew. The entire village, with the exception of Nemorino himself, is soon aware of this fact, and the village girls lose no time in deciding to see the gloomy young man – who has now downed the entire bottle of potion he has just purchased from Dulcamara – in a much more positive light. Adina is irritated to see the boy so cheerful and surrounded by girls. The doctor, for his part, starts to believe that he actually has invented a miracle drug. One after the other, the girls ask Nemorino to dance, practically dragging him by the hair.
Adina learns from Belcore that the boy has joined the army for money. The girl realises that she feels love for Nemorina and that if the boy won't even look at her now, she will have only Amor's vengeful doings to thank.
Dulcamara tells Adina that he gave Nemorina a love potion because the lad was in love with a girl whose heart is cold as ice. Hearing the story, Adina falls even further in love with him, if only because he enlisted as a soldier for her sake. Now she regrets rejecting Nemorino's love so many times, and all she wants is him.
When they meet again, Nemorino plans to maintain a cool demeanour towards the girl until she confesses her love for him.
Having purchased the recruitment letter back from Belcore, Adina now happily returns it to Nemorino. She pleads with him to remain in the village, where everyone loves him. When Adina bids him farewell, Nemorino remains determined to go off to battle. He'd rather die than live without the girl's love.
At this point, Adina goes ahead and tells Nemorina that she loves him. She regrets having tormented him over the years, and now she wants to make him happy at last.
Belcore arrives and is about to kill his competitor. But when he hears Adina say that she loves Nemorina, Belcore gallantly steps aside. Now everyone who did not already know learns that Nemorino has inherited a great fortune. Dulcamara attributes all this to the miracle drug, which the entire village is now eager to buy. Belcore alone knows what a quack the miracle doctor really is.