On admission to a pain management unit, 92.5% of 174 cancer patients suffered from more than moderate pain despite prior treatment. This inefficacy was mainly due to underdosage of drugs, inadequate intake schedule, and hesitation to use strong opioids. Following introduction of an oral drug therapy based on World Health Organization (WHO) guidelines, more than 80% of all patients described their pain as ranging between "none" and "moderate" on a six-step verbal rating scale at all times. To obtain these results, it was necessary to adapt the therapy to increasing pain in the course of terminal disease. Step III (strong opioids) gained more and more importance with time, and step I (nonopioids) was finally useful only in a minority of patients. Side effects played a minor role as a reason to change therapy. Oral drug therapy following these guidelines led to sufficient pain control in most patients over the whole study period (7,400 days); only 11% of the patients required other methods of pain management.