A paediatric clinical trial conducted in a developing country is likely to encounter conditions or illnesses in participants unrelated to the study. Since local healthcare resources may be inadequate to meet these needs, research clinicians may face the dilemma of deciding when to provide ancillary care and to what extent. The authors propose a model for identifying ancillary care obligations that draws on assessments of urgency, the capacity of the local healthcare infrastructure and the capacity of the research infrastructure. The model lends itself to a decision tree that can be adapted to the local context and resources so as to provide procedural guidance. This approach can help in planning and establishing organisational policies that govern the provision of ancillary care.