Rome’s empire rested heavily on Greek culture, which the Romans had recognized as superior in sophistication. On conquering portions of Alexander’s former empire, Rome found itself in possession of Greek philosophy, literature, sports, and medicine.
Greek medical theory was based on the Four Humors, the way each body predominated in one of four bodily fluids: black bile, yellow bile, blood, and phlegm. Medical treatment was tailored to which type of body you had, because illness was seen as an imbalance. This theory came straight into medieval Europe through Rome, so much more about that as we go on.
Rome’s army had infirmaries, but Greek culture had the Aesclepion. This temple to Aesclepius, god of healing, served both as a temple and as a sort of healing spa. The main Aesclepion in Epidaurus, Greece grew until, in Roman times, it was a very large facility that could house the seriously ill and dying.
Aesclepion healing theory began with the Four Humors, so on entering, a patient did a course of catharsis. This involved fasting, purging, and bathing. The patient also made sacrifices to the god and sought visions in dreams in which the god might tell them how to be healed. Priests interpreted these dreams and prescribed courses of treatment. An Aesclepion often had the god’s totem animals — rooster, snake and dog — on the premises and looked for them to appear in dreams.
The biggest cultural weakness of Greek and Roman medicine is that there was not a strong culture of caring for the sick. In two well-documented plagues, the sick were often abandoned. The first of them, in 165, is known as the Plague of Galen because this famous Greek doctor wrote about it. But Galen himself survived by leaving the city and avoiding contact with the sick. It seems that the same issue during the second plague, in 251, led to a much higher mortality rate among pagans than among Christians. Survivors who had been cared for by Christians tended to convert, and this event was probably a tipping point for the Roman Empire to stop persecuting the new faith.