The use in medicine of stars (the 12 signs of the zodiac) and of the sun, moon and planets is an ancient practice. However, the practice reached its epitome in Europe in the late medieval (1450+ AD) and early modern periods (1700 AD). During this period, medical practitioners regarded different signs of the zodiac and planets as having governance over different parts of the body, as controlling different diseases, and as affecting the usefulness of different drugs.
For example, to be effective, plants and herbs had to be collected during the times in which their associated planets were visible. These times were calculated from an almanac in which the rising and setting times of planets were given. To gather the medicinal plants and herbs at any other times would prevent them from being effective.
Other treatments besides herbal remedies were also thought to be governed by astrological signs. For example, bleeding, a common medical procedure until the early 19th century, was considered most effective when the moon was in a particular constellation.
Medieval scientists and medical practitioners saw the solar system being made up of seven planets. They treated the sun and moon as planets, and added to them Mercury, Venus, Mars, Jupiter and Saturn. These were the planets that could be seen with the naked eye. After the invention of the telescope in 1608 Uranus, Neptune, Ceres and Pluto were discovered and added to the list of astrological influences.
| Planets | Body Parts |
|---|---|
| Mercury and Uranus | Brain, nerves |
| Mercury | Nerves |
| Sun | Heart |
| Mars | Arteries |
| Saturn | Veins |
| Venus | Kidneys |
| Jupiter | Liver |
| Venus | Digestive system |
| Mars | Muscles |
| Venus and Mars | Reproduction system |
| Neptune and Uranus | Endocrine system |
| Moon | Ovaries |
| Saturn | Skin |
| Mars | Teeth, nails and hair |
| Saturn | Bones and skeleton |
| Planets | Diseases |
|---|---|
| Sun | Heart and spine disorders |
| Mars | Cuts, injuries and bruises, fefers, inflammations (with redness and heat) |
| Jupiter | Liver disorders |
| Sun or Jupiter | Diseases of expansion and excess |
| Moon | Menstural and mammary complaints and fluid retention (dropsies) |
| Venus | Urinary problems |
| Saturn | Diseases of decline, collapse, wasting, blockages and contraction |
| Saturn | Poisoning |
| Mercury | Tremors, neuroses |
| Mercury | Insanity |
| Venus | Digestive disorders |
The twelve Zodiac signs below cover the body from head (Aries) to toe (Pisces) because Aries is the first sign of the zodiac while Pisces is the last. Physicians diagnosing an illness would determine the constellation that the moon appeared in when his patient first became ill. He would then consult astrological predictions and associations and make a diagnosis.
| Aries | Head, face, brain eyes |
| Taurus | throat, neck, thyroid gland, vocal tract |
| Gemini | arms, lungs, shoulders, hands, nervous system, brain |
| Cancer | chest, breasts, stomach, alimentary canal |
| Leo | heart, chest, spine, spinal column, upper back |
| Virgo | digestive system, intestines, spleen, nervous system |
| Libra | kidneys, skin, lumbar region, buttocks |
| Scorpio | reproductive system, sexual organs, bowels, excretory system |
| Sagittarius | hips, thighs, liver, sciatic nerve |
| Capricorn | knees, joints, skeletal system |
| Aquarius | ankles, calves, circulatory system |
| Pices | feet, toes, lymphatic system, adipose tissue |
Astrology was an important part of medicine until the end of the 17th century.
Sources for how astrology was used to diagnose and treat disease in medieval times:
http://www.faqs.org/health/topics/98/Astrology-and-medicine.html#ixzz0mRdylj3T