In 50 patients, aged 16 to 58, an autologous blood patch was injected into the epidural space immediately after diagnostic lumbar puncture. The incidence of postpuncture headache was 22%, which was significantly lower than in a control group (40 patients, aged 17 to 54), where it amounted to 45%. Compared to the control group, the patients with epidural blood patch had significantly less postpuncture complaints between the 1st and 3rd day following lumbar puncture. Lower back pain as the only side effect was experienced by 30 to 40% of the patients in each of the 2 groups. We conclude that the epidural blood patch is practicable and effective in the prophylaxis of postpuncture headache, but cannot prevent its occurrence in all cases.