Only one medicine: the future of comparative medicine and clinical research

This article reviews the roots of comparative medicine and argues that during the 20th century it failed to realise its full potential. New opportunities arise from the growing availability of precise, minimally invasive, clinically compatible techniques, which enable us to benefit from the availability of spontaneous analogues of human disease in animals. Particularly with multifactorial diseases, these offer a unique blend of authenticity and acceptability. To realise the full benefits to both animals and humans, we need much closer alignment of human and veterinary clinical medicine.