The overuse of analgesics in patients with chronic daily headache (CDH) perpetuates and worsens the headache. The aim of this study was to evaluate the clinical response to withdrawal of analgesics and to preventive treatment in a group of patients with CDH. Eighty-four patients who were taking daily symptomatic medications, and suffering from CDH were studied. Treatment consisted of withdrawal of daily symptomatic medications and prophylactic therapy. Improvement was considered when intensity and frequency of the headache were reduced more than 50%. After a 2-15 months follow-up, 57 of the 76 patients that continued in the study had improved. From these, 98% had reduced the consumption of analgesics below the figures considered as abuse and a 94% took the prophylactic medications correctly. After giving up the preventive treatment, 26% of the patient presented CDH and the 60% overuse again of analgesics. These results show that withdrawal of analgesics is necessary for improvement in patients with CDH, but the possibility of relapses is elevated. We think that there are other factors implicated in the development of CDH. We therefore believe that in order to avoid the relapses this group of patients need follow-up and preventive treatments during long periods of time.