Since the beginning of the 21st century, the living conditions of undocumented migrant workers in Belgium have deteriorated drastically. In Brussels, after various social actions, undocumented people began squatting and occupying public buildings to make their struggle visible to society. Desperate, some seized the possibility of a loophole in Belgian law that permits ill persons to have access to a temporary residence permit and started hunger striking. Confronted with consecutive strikes, medical teams of voluntary health professionals faced a big dilemma. A search of the medical literature yielded information about the overall and specific tasks of health professionals during hunger strikes in custodial and hospital settings, but no scientific guidelines were found to address the specific problems the team was confronted with. Information was collected about 15 hunger strikes over a period of seven years, involving the participation of 1,158 strikers. This article describes the medical, organizational, and ethical difficulties encountered in the follow-up of hunger strikes in non-custodial settings, including those associated with the establishment of a health-care structure, operation with very limited resources, and communication with the media and other health professionals.