An ability to recognise symptoms of serious illness is essential for all front-line professionals in health care. Presented here are the red flag indicators of major disease in need of urgent intervention and the amber flag warnings of a need for urgent assessment. Each is linked to a reason why intervention is required to aid understanding and recall. The Little Book of Red Flags is a practical handbook to help early diagnosis of life-threatening conditions.The authors, Dr Ian Hill-Smith MD MRCP FRCGP and Dr Gina Johnson MB BS MSc MRCGP are highly experienced GP's who run accredited diploma courses in urgent care and are co-authors, along with their colleague Dr Chirag Bakhai, of the best-selling Minor Illness Manual, now in its 5th edition.