In this prospective study of 239 patients, 88 (37%) suffered from post-lumbar puncture headache (PPH). The pain was located within the region innervated by the trigeminal nerve in 49% of the drawings, within the occipital and/or suboccipital region in 11%, and within the combined trigeminal/occipital region in 39%. The headache was unilateral at least once in 34% of the patients. Changes in pain location from one region to the other and/or between bilateral and unilateral headache were observed in 54% of the patients throughout the PPH period. Associated symptoms were experienced by 85%, nausea (73%) and dizziness (60%) being the most frequently reported. In the upright position, nausea, dizziness, and tinnitus tended to be present during a fairly large part of the PPH period (57-63% of the days), vomiting occurring only occasionally (28%). The intensity of associated symptoms was positively correlated to PPH severity. Pain in the combined trigeminal/occipital region was most severe and related to more associated symptoms than pain in other regions, and unilateral pain was milder than bilateral pain. Pain in the occipital and/or suboccipital region was mildest. The severity of nausea decreased significantly on the last 2 days of the PPH period, and the intensity of dizziness decreased when PPH was about to subside. Tinnitus is probably due to a cochlear dysfunction, and presents special characteristics. Its incidence was not clearly related to PPH severity and it increased with increasing duration of PPH; its intensity did not decline when PPH was about to wane.