The 2-deoxy-D-[1-14C]glucose method was used to map effects of morphine withdrawal on glucose utilization in the rat spinal cord. Naloxone (0.5 mg s.c.) given to morphinized rats (225 mg morphine over 7 days) produced a withdrawal syndrome, and increased glucose utilization in the superficial layers of the dorsal horn in the cervical and thoracic spinal cord. The findings are consistent with an increased input from small diameter primary afferent fibers during the morphine withdrawal syndrome.