Interpleural analgesia was used to alleviate acute, severe exacerbations of chronic pain unrelieved by pharmacologic therapy in ten terminally ill cancer patients. Pain from metastatic disease to the neck, arms, chest, brachial plexus, thorax, or abdomen was effectively eliminated between 7 hr and 40 days in nine patients, who died with minimal or no pain. The technique was performed primarily using bupivacaine. No side effects were detected. Interpleural analgesia appears to be effective in rapidly controlling acute exacerbations of cancer pain in terminally ill patients. Moreover, it may also be a suitable therapy for moribund patients when used as a continuous-infusion technique.