The objectives of this paper are to lay out for wider discussion the potential advantages and disadvantages of active military units providing medical care for the local population through ad hoc clinics (MEDCAPS). The literature on this subject has been reviewed and the personal experience of MEDCAPS by the author and other doctors in Helmand Province 2007/8 is presented. Although in the published literature, MEDCAPS are almost universally regarded as being good for relations between the military and civilians, the reality on the ground is that they potentially risk the lives of both staff and patients. and may actually contribute little in terms of relieving suffering, or improving relations between military and civilians. The conclusion of this paper is that MEDCAPs at best have a very limited and specific role, but that there will remain a strong desire from staff on the ground to initiate them.