Peacekeeping operations have become the main operational activity of the armed forces of the developed world over the past 10 years--a trend which appears likely to continue. Peacekeepers often remain deployed long after the armed conflict has ceased to help reconstruct civilian infrastructure. It is often possible to use the excess capacity of medical support units deployed with military forces to provide help to the local population. While this is appropriate immediately after a conflict when civilian clinics are overwhelmed, in the more prolonged reconstruction phase the seemingly simple clinical imperative to treat as many patients as possible becomes more complex.