Forty postpartum patients with postdural puncture headache (PDPH) were randomly assigned to receive oral caffeine (300 mg) or a placebo. Intensity of headache, quantitated using a visual analogue pain scale (VAS), was assessed immediately before drug administration and 4 and 24 h later. Relief of PDPH measured as delta VAS (initial VAS - VAS at 4 h) was significantly better in the caffeine than in the placebo group (P = 0.014). Six patients (30%) whose PDPH was relieved by caffeine at 4 h had recurrence of symptoms the following day. Our study demonstrates that caffeine administered orally provides relief, albeit if sometimes transient, from PDPH with minimal side effects.