Article by David Osborn

In Medical Astrology, each planet represents a certain set of physiological or metabolic functions tied together by a common theme, which concerns the planet’s inherent nature and temperament. And, like everything else in Greek Medicine, even the far-flung planets have their own inherent nature and temperament.

The main parameters for measuring a planet’s nature and temperament are the Four Basic Qualities. Each of the Four Temperaments has planets that resonate with its influence.

The hot, dry, fiery, Choleric planets are Mars and the Sun. Of course, Mars is the principal Choleric planet, especially concerning pathology, as it concerns heat, fevers, infections, inflammation, bilious conditions and the like. The Sun concerns the righteous, normal fire of the organism, what Greek Medicine calls the Innate Heat, as well as the other vital principles – the Vital Force and Thymos, or the immune force of the organism. The Sun also represents the heart, the principal organ of the Vital Faculty. In Ayurvedic terms, the Innate Heat would be Agni, and the Vital Force Prana.

Jupiter is the principal Sanguine planet, ruling expansion and growth; it represents the liver, the principal organ of the digestive system and Natural Faculty, which governs digestion and metabolism, nutrition and growth. It is assisted by Venus, which is mainly Sanguine, but slightly colder and more Phlegmatic in temperament. It’s interesting to note that the Sanguine temperament, considered to be the choicest and most desirable in Greek Medicine, is represented by Jupiter and Venus, the major and minor benefics.

Both planets have a warming, moistening, enriching influence.

The Melancholic temperament is also called the Nervous temperament, and is cold and dry. It is represented by Mercury and Saturn, which also share these qualities.

Mercury, while cold and dry, is also light, quick and mobile in nature.

It represents the Nervous temperament, the nervous system, and the throat, lungs and respiratory tract. Mercury also rules speech and communication.

Saturn, while cold and dry, is also heavy and slow in nature. It is mainly concerned with the functions of the black bile humor, especially the bones and connective tissue, which require black bile for their formation, and with black bile’s storage receptacle, the spleen. Saturn is also associated with common pathologies of aggravated black bile, like arthritis and rheumatism.

Metabolically speaking, Jupiter and Saturn are complementary opposites.

Sanguine Jupiter favors growth, expansion, enrichment and excess, whereas Melancholic Saturn favors aesthenia, wasting, hypometabolism and deficiency.

The principal Phlegmatic planet is the Moon, which rules all fluid metabolism in the body. The Moon is also very nurturing and anabolic, being associated, along with her domicile sign of Cancer, with the stomach and the female breasts. The Phlegmatic Moon is the complementary opposite to the Choleric Sun; together, these two luminaries represent the core Yin – Yang, Water – Fire principles of physiology and metabolism. The Moon is assisted in her Phlegmatic functions by Venus, the other feminine planet.

In addition to the seven classical planets, the Ascendant or Rising Sign, called Horoskopo in classical Greek astrology, is also very important. The Ascendant, although not actually a planet, is probably the single most important planetary factor in Medical Astrology, because it represents the physical body – its basic structure and appearance, and inherent constitutional strengths and weaknesses. In terms of its inherent temperament, the Ascendant is pretty neutral, and varies according to its sign, and the planets conjuncting or aspecting it.

The outer planets also have their inhernet natures and temperaments, even though they weren’t part of classical Greek or Hellenistic Astrology. They are as follows:

Uranus, being the higher octave of Mercury, is Nervous or Melancholic in temperament, but primarily Nervous, being associated with nervous and spasmodic afflictions.

Neptune is primarily Phlegmatic in nature, being associated with the psychic sensitivity of the Water element. Medically, Neptune rules the lymphatic system.

Pluto, I feel, has a dual nature and temperament: Its intense, passionate drive as the higher octave of Mars makes it partially Choleric, but its ability to plumb and purge the dark subliminal depths of the psyche and subconscious mind also makes Pluto Phlegmatic. Together, the Choleric Fire and Phlegmatic Water principles of Pluto interact in a dance of both mutual destruction and mutual regeneration and transformation.

Hard aspects between certain planets in the natal astrology chart can show tendencies towards excess or aggravation of a certain humor or temperament.

With the Sun and Mars, these aggravations would be Choleric in nature.

With Mercury and Saturn, or Saturn and Uranus, they would be Nervous or Melancholic. With Venus and Jupiter, Sanguine afflictions like diabetes are common.

There is a lot that Medical Astrology has to say about the planets that I have left out of this discussion. While this information is also valid, I have chosen to focus on aspects of the planets that are little understood and appreciated, but deserve to be better known, which concern the basic principles of Greek Medicine as the original source and foundation for Medical Astrology in the West.