We recently reported a meta-analysis of 94 randomized placebo-controlled trials of blood pressure-lowering drugs in which the prevalence of headache was reported [1]. On average, one-third fewer people reported headache in the treated groups than in the placebo groups [odds ratio (OR) 0.67; 95% confidence interval (CI) 0.61, 0.74; P < 0.001]. There was a statistically significantly reduced prevalence of headache in separate analyses of four classes of blood pressure-lowering drugs, thiazides, β-blockers, ACE inhibitors and angiotensin-II receptor antagonists, an observation that suggested that blood pressure reduction itself prevents headache.