General practice encounters often involve vague symptoms, potentially representing illness in its early stage. Managing such undifferentiated symptoms is difficult, but one of the key tasks of the general practitioner is to discover serious disease at an appropriate stage whilst also minimising over-investigation. Although the diagnostic process and methods of coping with uncertainty in general practice have been described, the early course of disease, especially undifferentiated presentations, is poorly understood. There is still much to learn about diagnosis in general practice, and important contributions could be made by researchers in any primary care setting.