The transient receptor potential vanilloid type 1 (TRPV1) receptor is a nonselective cation channel gated by noxious heat, protons, and capsaicin. TRPV1 is present in primary sensory neurons and in both central and peripheral sensory nerve terminals and plays a role in thermal and mechanical hyperalgesia. SB-366791 is a selective TRPV1 antagonist that is widely used in pain research. In cultured trigeminal ganglion neurons, SB-366791 inhibits capsaicin-evoked Ca2+ influx with an IC50 value of 0.7 µM. A 1 nmol injection of SB-366791 in mouse paw reduces capsaicin-induced nociceptive responses in a model of pain. Intrathecal pretreatment of 10 µl SB-366791 in rats suppresses tolerance to the analgesic effects of chronic morphine administration. Co-administration of morphine and SB-366791 at 0.1 mg/kg has potent analgesic effects in a mouse model of bone cancer pain.