The College of Physicians of Philadelphia Digital Library

Under the Influence of the Heavens: Astrology in Medicine in the 15th and 16th Centuries


Before the ideas of Scientific Revolution began to emerge in the mid-16th century, a wholly different view of the natural world dominated the psyche of Western Europe. The lines between the heavens and earth were porous, and it was believed that what happened in the stars governed what happened on terra firma. In addition to predicting meteorological events and guiding business decisions, astrology was used as a tool for both treatment and diagnosis of any number of aches and pains. Depending on the sign of the zodiac under which a patient was born, the astrologer physician could then make recommendations for treatment based on the placement of the moon and stars in the sky at a particular moment in time. Astrological medicine was also closely related to humorism. An imbalance in the four humors—black bile, yellow bile, phlegm, and blood—could be both explained and corrected by consulting the stars. This method of medical treatment was included in a number of encyclopedias from the earliest centuries of the Common Era, peaking in the Middle Ages, and remaining popular in the 15th and 16th centuries.


Exhibit co-curated by Annie Brogan and Robert D. Hicks; adapted for the web by Joseph Anderson and Sarah Schwab.