The effort to develop therapies that improve outcome after acute ischemic stroke should bear fruit in the near future. The availability of effective, safe and economical neuroprotectants as a spin-off from this effort will lead to the evaluation of prophylactic neuroprotection in selectively targeted populations. We propose three types of prophylactic neuroprotection and patient groups that might be evaluated in appropriate clinical trials. We anticipate the identification of other patient groups and more effective neuroprotectants. The medical community which directs its efforts at stroke prevention and acute therapy will have to consider and evaluate prophylactic neuroprotection along with the other two therapeutic approaches of prevention and acute therapy. This prophylactic-neuroprotection hypothesis should be testable in the near future. We welcome further debate and suggestions.