How to Tell if Someone Is or Is Not Dead, c. 1380

historiated initial with doctor holding something to patient's face He’s not dead yet.
BL Harley 3140, f. 39r (14th c.)

Moreover, if there is any doubt as to whether a person is or is not dead, apply lightly roasted onion to his nostrils, and if he be alive, he will immediately scratch his nose.

Johannes de Mirfield, Breviarium Bartholomei (c. 1380-95) (trans. Percival Horton-Smith Hartley and Harold Richard Aldridge)

Don’t bother looking for a pulse. The onion reflex is the only reliable sign of life.