Antoine Roquentin is the protagonist of Nausea. The novel is framed as diary entries he wrote over several weeks at the beginning of 1932. Antoine is a reclusive, 30-year-old historian staying in the city of Bouville to research the historical (and fictional) 18th-century aristocrat the Marquis de Rollebon. Antoine becomes increasingly alienated from the people and the city around him as the novel progresses. Antoine is indecisive, frozen by all the freedom he possesses; he is arrogant, believing he alone understands the truth about existence and that nobody else around him does; he is also unable to connect with the people around him due to his assumed superiority.

Antoine becomes increasingly isolated as the novel progresses. His only consistent human contact occurs with Françoise, the owner of the Railwaymen’s Rendezvous, and Ogier P., the Self-Taught Man. Antoine has sexual relationships with a few other unnamed women, such as the owner of the Rendezvous des Cheminots. Antoine’s revelations about existence cause him to view his relationships with these women with increasing disgust. He begins dehumanizing them by using metaphor to make their bodies inhuman. The woman at the Cheminots becomes “a small garden with low, wide trees on which immense hairy leaves were hanging” that is overrun with ants, centipedes, and other repulsive creatures (59).