An autoimmune disease occurs when the body creates antibodies that attack itself. O’Rourke’s illness throughout the book is thought to be related to various autoimmune diseases. These are historically under researched and poorly treated by the American medical system.

A disease O’Rourke is diagnosed with early in the book, in which the immune system attacks the thyroid gland. Also called “autoimmune thyroiditis,” this disease causes a decline in hormone production that affects the metabolism, often leaving people sluggish and devoid of energy.

Generally speaking, inflammation is a word that describes what happens when the body’s immune system detects a problem and responds to heal wounds and fight infections. Although inflammation can be a helpful mechanism for healing, chronic inflammation is harmful to the body and is related to autoimmunity. In O’Rourke’s experience, inflammation is a word she first learns when exploring the nuances of integrative medicine.