Dutch researchers performed a meta-analysis of placebo-controlled RCTs to estimate the effect of fibre supplementation on blood pressure (BP) overall and in population subgroups. Original articles published between 1 January 1966 and 1 January 2003 were retrieved for 24 trials that fulfilled the criteria for meta-analysis. Data were abstracted on fibre dose, fibre type, BP changes, study design features and study population characteristics. Fibre supplementation (average dose 11.5 g/day) changed systolic BP by −1.13 mm Hg and diastolic BP by −1.26 mm Hg. Reductions in BP tended to be larger in older (> 40 years) and in hypertensive populations than in younger and in normotensive ones.