To help him in the enterprise, in addition to his servant Siro, is Ligurio, who has a great influence on Nicia; Ligurio advises Callimaco to pretend to be a doctor and to convince the notary to let his wife drink an infusion of mandragola, capable of curing her presumed sterility (in fact it is Nicia who is sterile: according to a belief then widespread, a man who was not impotent must necessarily have been able to procreate).

However, this magical cure has a contraindication: whoever has the first sexual relationship with the woman will be infected with the poison of the mandragola and will die within eight days.

To remedy the problem and at the same time protect Nicia's honor, all you have to do is meet her secretly with the first street "boy" who will absorb all the deadly poison.

This time also the mother Sostrata and the friar Timothy will intervene, who playing on her Christian devotion - dramaturgically important the biblical quotation of Lot and the daughters - will convince her to "cure".

That night Callimaco will disguise himself as a beggar and will be carried by the husband himself into the arms of his wife, who will not be satisfied with this fleeting encounter but will want to reiterate it in the time to come.