Trepanning, the procedure of cutting a hole in the skull, is the earliest known medical operation. Some anthropologists believe that trepanning was performed on people with mental illnesses to drive out evil spirits from their heads. This skull dates from the Inca civilization.
Our understanding of prehistoric medical practice is from the study of ancient pictographs that show medical procedures, as well as the surgical tools uncovered from anthropological sites of ancient societies.
Serious diseases were of primary interest to early humans, although they were not able to treat them effectively. Many diseases were attributed to the influence of malevolent demons who were believed to project an alien spirit, a stone, or a worm into the body of the unsuspecting patient. These diseases were warded off by incantations, dancing, magic charms and talismans, and various other measures. If the demon managed to enter the body of its victim, either in the absence of such precautions or despite them, efforts were made to make the body uninhabitable to the demon by beating, torturing, and starving the patient. The alien spirit could also be expelled by potions that caused violent vomiting, or could be driven out through a hole cut in the skull. This procedure, called trepanning, was also a remedy for insanity, epilepsy, and headache.
Surgical procedures practiced in ancient societies included cleaning and treating wounds by cautery (burning or searing tissue), poultices, and sutures, resetting dislocations and fractures, and using splints to support or immobilize broken bones. Additional therapy included laxatives and enemas to treat constipation and other digestive ills. Perhaps the greatest success was achieved by the discovery of the narcotic and stimulating properties of certain plant extracts. So successful were these that many continue to be used today, including digitalis, a heart stimulant extracted from foxglove.
Several systems of medicine, based primarily on magic, folk remedies, and elementary surgery, existed in various diverse societies before the coming of the more advanced Greek medicine about the 6th century bc.