The naïve and shy Nemorino has fallen unhappily in love with the rich and beautiful Adina. At her friend Giannetta’s wedding, Adina entertains everyone present with the story of Tristan and Isolde and how they are bound together by a love potion. At this point Sergeant Belcore appears and starts courting Adina with great confidence. However, despite all this ambitious officer’s efforts, he doesn’t stand a chance with her. When he ultimately proposes marriage to her, she rejects him. Nemorino has observed this entire scene with trepidation. No sooner has Belcore left with his troops, than he confesses his love to Adina. But she laughs at him and advises him not to take love so seriously.
Dulcamara appears at the celebrations amid considerable pomp. He praises his potions as miracle cures to make all your woes disappear and sells them to everyone present. As soon as the crowd surrounding him has dispersed, Nemorino takes his chance to ask Dulcamara about Isolde’s love potion. Dulcamara exploits the young man’s naivety to sell him a bottle of Bordeaux as a love potion. However, he emphasises that this will only take effect after 24 hours. When Nemorino meets Adina after taking the first drops of this elixir, he seems a different man. He assures her he will now take a lighter view of love and forget his love worries within a few days. Adina’s pride is hurt by Nemorino’s sudden coldness and she decides to test him. When Belcore joins them, she accepts his proposal after all and promises to marry him in six days, at which Nemorino can only laugh. Yet when the message arrives that Belcore and his troops have to move on and Adina decides to marry him immediately, he is once again in despair. Nemorino begs Adina in vain to postpose the wedding and everyone thinks he is behaving like a madman.
The wedding celebrations are in full swing and, together with Adina, Dulcamara presents a comedy he has written. Together they perform the “Song of the gondola girl and Senator Tredenti”. Adina, still wanting revenge on Nemorino, is determined not to sign the marriage contract until he is there, in order to humiliate him. Meanwhile, Nemorino is having doubts about the love potion’s effectiveness and demands that Dulcamara give him another bottle. However, as he does not have any money, he allows himself to be recruited by his rival Belcore, in order to use the money he is given for enlisting to pay for the love potion.
In the meantime it becomes known that Nemorino’s wealthy uncle has died and left his entire fortune to his nephew. Suddenly Nemorino is surrounded by women and to begin with he does not know what is happening to him. Dulcamara cannot believe his eyes and suddenly starts believing that his love potion actually works. He recommends it to Adina, who has been stung by Nemorino’s popularity with all the women. In this way she learns about the love potion and also that Nemorino has sold himself in order to be able to afford it.
Nemorino has seen her have to wipe away a tear when she saw him surrounded by the other women. Adina has now bought back his enlistment papers from Belcore and finally confesses to Nemorino that she loves him. Nemorino discovers his inheritance and Dulcamara is convinced that his potion is capable of generating not only love but wealth too. Apart from Belcore, who curses his rival, everyone is happy and praises Dulcamara’s love potion.