This article explicates a theory that oxytocin, a sexually dimorphic neurotransmitter and paracrine hormone, is a plausible mechanism linking early relational trauma with posttraumatic self disorders (e.g., dissociation, somatization, and interpersonal sensitivity), posttraumatic stress disorder, and pelvic visceral dysregulation disorders (e.g., irritable bowel syndrome, chronic pelvic pain, interstitial cystitis, and hyperemesis gravidarum). This posttraumatic oxytocin dysregulation disorders theory is consistent with the historical and contemporary literature.