On the farm of the young and rich Adina the reapers meet after a morning of work. Giannetta, Adina’s girlfriend, rewards workers with fruit and wine. In this joyful atmosphere, Nemorino, a young peasant in love with Adina, thinks she will never be able to aspire to her, considering her more intelligent and more cultivated.
Adina appears amused by the new book read, the story of Tristan and Isolde. At the request of the reapers she will read this fragment. Reading is interrupted by the sound of a drum announcing the arrival of the new guard, headed by Sergeant Belcore. This, in a ceremonial way, gives Adina a bouquet of flowers. Belcore, conceited and confident, makes her the court of Adina asking for her wife. Adina, a little amused by the situation, tells Belcore that she cannot be so easily conquered. Belcore gives orders to the soldiers, and Adina sends his men to work. Nemorino tries again to convince Adina of the sentiment of his feelings, but she, as if as usual, rejects her love, considering that independence is more valuable. Nemorino is not convinced by Adina’s arguments, continuing her statement. Their conversation is interrupted by a trumpet sound. Peasants announce the appearance of a foreign character who arrives with a whole suite. Arriving in the middle of the curious crowd and surprised by this appearance, he reveals his identity.
Dulcamara, “encyclopedic doctor”, “human benefactor, repairer of evil, healing of any disease” is in fact a sympathetic charlatan who, under the pretext of the “universal elixir” that he sells to all his wishes, earns his existence. Peasants, believing in the power of the miraculous elixir, buy it with all confidence.
Marked by the discussion with Adina, Nemorino asks Dulcamara for “Queen Isolda’s elixir” that helped her to love Tristan.
The “encyclopedic doctor” is happy to have found a buyer yet. In fact, the supposed elixir is nothing but Bordeaux wine. Dulcamara, after explaining how to use the licorice, tells him that it will only be the next day that he will have effect on his beloved woman, while the queen doctor will have time to disappear from the village.
Staying alone, Nemorino tries the “miraculous” drink.
Bordeaux wine makes its effect, cheering on it. Adina is surprised by her strange indifference. Belcore’s appearance gives Adina the idea of revenging on Nemorino’s attitude, accepting the Sergeant’s fanfare’s marriage request. Adina will fix your wedding in six days. Giannetta, together with the soldiers, gives the commander the unpleasant news of their departure the next morning. The order of departure causes Adina to rush the wedding for that evening. Nemorino, believing in the miraculous elixir that would take effect the next day, tries to persuade Adina to give up her decision. Adina, along with Belcore, and the peasants amuse Nemorino’s state of restlessness, believing him to be mad. Adina invites everyone to the wedding, and Nemorino remains alone and desperately, asking for help from the alleged doctor.
Wedding preparations being made, expect the coming of the notary to celebrate the marriage. The invitees sing in honor of the happy couple as she gets upset because of Nemorino’s absence. Dulcamara, also invited to the party together with the beautiful bride, plays a bargain, enthusiastic about the auditor. Belcore announces the arrival of the notary. The guests and the grooms are headed to Adina’s house to officiate marriage. Dulcamara, taking advantage of the fact that he can stay alone, sits quietly to eat from the rich wedding table. Nemorino, who has noticed the retired from a retracted corner, is asking for help from the doctor asking him to sell him a bottle of elixir. Dulcamara asks for this favor a much higher amount than the first, a sum that Nemorino does not have. Belcore appears from Adina’s house, wondering that his future wife postponed the signing of the marriage act in front of the notary. Seeing Nemorino angry, Belcore asks him what the reason for his despair is. Finding that the lack of money is the cause of the desperation of the young peasant, Belcore proposes a solution: to enlist a soldier under his command against the sum of twenty yellow. Nemorino accepts the solution by signing a contract. Giannetta brings to the peasants the news that Nemorino’s wealthy uncle died leaving him a fabulous fortune. Nemorino, who drank the second bottle of “elixir” bought from Dulcamara with his contract money with Belcore, in his euphoric state is assaulted by Giannetta and peasants, all considering the young heir to be an excellent match. Nemorino, unaware of the real reason for unexpected assault on them, thinks the elixir has made its effect.
Dulcamara and Adina are surprised to see this change: “the doctor” begins to believe that his drink is indeed miraculous, and Adina becomes jealous seeing Nemorino surrounded by girls.
Girls take Nemorino to dance, and Dulcamara remains to talk to Adina. It wonders what the reason for transforming Nemorino. Dulcamara proudly states that it is his work, explaining to Adina that the power of alchemy is very great and that the “love potion” used by Queen Isolda is doing miracles. Adina remembers that Nemorino listened to the story of Tristan and Isolde’s love, and she realizes that he loved her for herself, and he also tried with all sincerity and conviction to use the same method. She also learns from Dulcamara that in order to obtain the miraculous elixir, Nemorino sells his own freedom, entering Belcore as a soldier. All these facts demonstrate Adina’s insistence on Nemorino’s feelings, regretting her attitude until now. Seeing that Adina loves, Dulcamara is trying to sell him a bottle of elixir. To his surprise, Adina prefers his own elixir: a glamorous smile, a gentle look, a comfort. Recalling the change of Adina’s attitude towards him when he was assaulted by girls, Nemorino realizes that the young woman loves him. Adina appears with Nemorino’s redeemed contract from Belcore asking him to stay in the village where all people love him for his modesty, sincerity and honesty. Nemorino, however, expects something else from Adina: the confession you loved for him. Otherwise, his departure to Belcore’s service is inevitable. Not to lose him, Adina finally admits he loves him. Belcore surprises the two young people hugged and without suffering too much, tells everyone emphatically that he can always have another wife. Dulcamara, eager to win some yellow, also sells a bottle of elixir. Considering his completed business and enough earnings, the “encyclopedic doctor” Dulcamara collects his original ambulance shop by separating himself from the villagers who, enthusiastically, bid farewell to him to return as soon as possible.