360 patients with cervical radicular pain were randomized to undergo interscalene brachial plexus block (IBPB) or a control block to determine their effects on upper limb, scapular and chest pain. At 5 minutes and 7 days after injection, the IBPB group experienced significantly less upper limb pain than the control group. Out of the 180 patients assigned to the IBPB group, 89 of these patients had symptoms of stellate ganglion block. The patients with stellate ganglion block symptoms experienced less scapular and chest pain than those without the symptoms. None of the control group patients reported symptoms of stellate ganglion block.