John Auer (March 30, 1875 – 1948) was an American physiologist and pharmacologist. He was a graduate of Johns Hopkins University Medical School (1902), and was son-in-law to physiologist Samuel James Meltzer (1851–1920), whom he closely worked with at the Rockefeller Institute for Medical Research.
The eponymous Auer rods are named after him, which are rod-shaped inclusions in the cytoplasm of myeloblasts. These were described by Auer in a 21-year-old patient suffering from a nosebleed and a sore throat.
Auer gave the first account regarding the physiological occurrences associated with anaphylaxis, which he researched in experiments on guinea pigs. He performed a number of studies with his father-in-law involving the correlation between bronchial asthma and foreign substances, and with Meltzer, he also investigated the effects of magnesium on tetany. The term "Auer's phenomena" is named for allergic inflammations caused by exposure to xylene, which he first described in experimentation on laboratory rabbits.
He is credited with ventilation of the lungs with anaesthesia during open thorax surgery. His technique of intra-tracheal intubation is used to give continuous respiration to patients without respiratory lung movement.