Medical astrology (traditionally known as iatromathematics) is an ancient applied branch of astrology based mostly on melothesia . the association of various parts of the body, diseases, and drugs with the nature of the sun.
Medical treatments were related to the zodiac in multiple ways. First, one must consider the patient's personality and constitution that were determined by the zodiac sign of one's birthday. Second, the affected part of the body and its sign must be considered. Third, the time of year or season when the patient became sick and its zodiac characteristics had to be assessed. Fourth, decisions about the best day for bleeding, purging, bathing, sweating, or other treatments were made based on the locations and phase of the moon in the zodiac. Finally, herbs and other medicines had to be selected for treatments while considering their associated astrological qualities.