Additional studies across diverse pain models have shown that mast-cell stabilizers and histamine-receptor antagonists reduce hyperalgesia [25,26], pelvic pain [27], inflammatory pain [28], and postoperative nociception [29], further supporting a central role for histamine-driven pathways in endometriosis-associated pain.; for instance, ketotifen, a mast cell stabilizer and HRH1 antagonist, has been shown to alleviate hyperalgesia in a rat model of surgically induced endometriosis. Here, HRH1 is linked to endometriosis.