Over the next few decades, many Western European countries will undergo a large demographic transformation introduced by the retirement of the "baby boomers" and the possibility of striking increases in longevity. The aim of this study was to estimate the effect of a growing and ageing Dutch population on the future consumption of pharmaceuticals, so as to be able to anticipate the potential future emissions of these pharmaceuticals and their residues to surface waters. A total of 354 prescribed pharmaceuticals from 40 therapeutic groups was selected for study. These constitute 1.251 metric tonnes (98%) of the total Dutch consumption of prescribed pharmaceuticals in 2007. Calculations based on a fixed consumption rate (2007) predict that demographic developments can be expected to push consumption up to 1.504 metric tonnes in 2020 (+17%) and 1.851 metric tonnes by 2050 (+37%). Therapeutic groups showing the largest increase are related to illnesses associated with old age. The only groups showing a decrease are the antivirals and drugs for addiction treatments as well as ethinylestradiol, an active compound in contraceptives.