Chiropractic dates back to 1895. However, some of the earliest healers in the history of the world understood the relationship between health and the condition of the spine. Hippocrates advised: "Get knowledge of the spine, for this is the requisite for many diseases."

Herodotus, a contemporary of Hippocrates, gained fame curing diseases by correcting spinal abnormalities through therapeutic exercises. If the patient was too weak to exercise, Herodotus would manipulate the patient's spine. The philosopher Aristotle was critical of Herodotus' tonic-free approach because, "he made old men young and thus prolonged their lives too greatly."

The treatment of the spine was still crudely misunderstood until Daniel David (D.D.) Palmer discovered the specific spinal adjustment. He was also the one to develop the philosophy of chiropractic which forms the foundation for the profession.  

On September 18, 1895, D.D. Palmer was working late in his office when a janitor, Harvey Lillard, began working nearby. A noisy fire engine passed by outside the window and Palmer was surprised to see that Lillard didn't react at all. He approached the man and tried to strike up a conversation. He soon realized Lillard was deaf.

Patiently, Palmer managed to communicate with the man, and learned that he had normal hearing for most of his life. However, he had been over in a cramped, stooping position, and felt something "pop" in his back. When he stood up, he realized he couldn't hear.

Palmer deduced that the two events, the popping in his back and the deafness had to be connected. He ran his hand carefully down Lillard's spine and felt one of the vertebra was not in its normal position. "I reasoned that if that vertebra was replaced, the man's hearing should be restored," he wrote in his notes afterwards. "With this object in view, a half hour's talk persuaded Mr. Lillard to allow me to replace it. I racked it into position by using the spinous process as a lever, and soon the man could hear as before."