Though antibiotics return O’Rourke to a sense of normalcy, they also destroy her gut microbiome, so on the advice of Matt Galen, she travels to receive a fecal microbiota transplant (FMT), a treatment that she never would have considered had her Lyme disease been diagnosed early on. However, years of searching for answers have changed her relationship to her body, and she understands that there are many intertwined factors that will lead to healing. In the clinic, O’Rourke receives her first of eight treatments over two weeks. The treatment is intended to repopulate her own gut with another person’s healthy bacteria. She then cites the history of how a Western diet high in processed foods has led to the extinction of healthy bacteria that used to live in the human gut. Beyond healing the gut, the treatment can also improve mood and the functioning of the brain.

O’Rourke ends up feeling incredibly sick from the treatment, a side effect that is supposed to assure its effectiveness. She returns home after five treatments, with a regimented diet to follow. Eight weeks after the treatments, O’Rourke gets pregnant. Despite her worries, being pregnant ends up making O’Rourke feel better, something common among many women with POTS and autoimmune diseases.