John Auer (March 30, 1875, Rochester, New York – 1948) was an American physiologist and pharmacologist. He was a graduate of Johns Hopkins School of Medicine (1902), and was son-in-law to physiologist Samuel James Meltzer (1851–1920), with whom he closely worked at the Rockefeller Institute for Medical Research.
The eponymous Auer rods are named after him, defined as rod-shaped inclusions in the cytoplasm of myeloblasts, myelocytes and monoblasts. These were described by Auer in a 21-year-old patient suffering from a nosebleed and a sore throat.
He performed a number of studies with his father-in-law involving the correlation between bronchial asthma and foreign substances, and also with Meltzer, he investigated the effects of magnesium on tetany. The term "Auer's phenomena" is named for allergic inflammations caused by exposure to xylene, about 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. He also gave the first account on the physiological occurrences associated with anaphylaxis; his research involving experiments with guinea pigs.