Sunday, May 8, 2016

What does Rx mean?

I was out to dinner the other night with my friend Bill. We were celebrating his retirement as a pharmacist. Just to be clear - I am not talking about my friend, Bill the Pharmacist who retired a year ago. Or my friend Linda the Pharmacist who also retired a year ago. Nor am I talking about my friend David, who hasn't said anything about retirement. Yet.

You can draw your own conclusions about why I have so many friends who are pharmacists. I will explain it as mere coincidence.

I don't know how the topic came up, but someone asked where the symbol "Rx" came from. Bill said it was an abbreviation for the Latin word for "recipe". The "x" on the tail of the "R" designates an abbreviation.

Inserting the Rx symbol in Word

For those who like simple answers to life's important questions, please feel free to accept that as your version of the truth. But for people like me, there always has to be a more contorted answer to simple questions. Here's what I told Bill.

It goes back to Hippocrates

Most everyone remembers Hippocrates. I'm not talking about that one character from some sitcom or other. I am talking about the Father of Medicine, the guy who is famous for the Hippocratic Oath.

Hippocrates taught that each part of the body is ruled over by one of the signs of the zodiac, as we see in the illustration below. Aries governs the head, Taurus governs the throat, as so on. Naturally, to understand how to care for the sick, a physician must understand astrology. Hippocrates had this to say about astrology: "A physician without a knowledge of Astrology has no right to call himself a physician." No kidding. He really said that.

The signs of the Zodiac calling dibs on this unfortunate fellow

This advice made it into the early Renaissance. 

Paracelsus (1493 - 1541) was a physician and philosopher who broke with Aristotle's view that we could discover truth by just thinking about things and making stuff up. Paracelsus taught that observation was more important than the dogma of the ancient Greeks. But he was stilled chained to the past in terms of astrology: 

“[Paracelsus] taught the doctrine of the microcosm and the macrocosm that forced the physician to become astrologer.”
(The Scientific Revolution 1500 – 1800, A. R. Hall, p. 133)

One historian tells us that Hippocrates' edict was alive and well in the early Renaissance.

“Between astrology and medicine, however, strong ties existed. The heavenly bodies were universally believed to influence human as well as other sublunary bodies: the good physician was supposed to always take astral influences … into account.”
(Medieval and Early Renaissance Medicine, Nancy Siraisi, p. 67)

Another historian is even more strident.

“Astrology also became closely associated with the practice of medicine: no reputable physician of the later Middle Ages would have imagined that medicine could be successfully practiced without it.” 
(The Beginnings of Western Science, David Lindberg, p. 279)

Here is yet another historian who tells us of how medicine was practice in medieval times:

“The progress of the planets, especially the Moon, was charted over succeeding days, with little or no observation of the patient himself, indeed the staunchest astrologer-physicians would claim that they did not even need to see the patient.”
(Astrology, A History, Peter Whitfield, p. 174)

Doing the patient's astrological chart was even more important than seeing the patient? Imagine that. I would hope that most of the readers of this blog find this at least a little bit absurd. 

I have written about the signs of mathematicians, and the signs of politically active rock stars. In both of these incredibly astute blog posts, I showed no correlation whatsoever between someone's sign of the zodiac and their proclivities. If you have read these blogs, you will likely have guessed that I don't rush to open my paper every day to read my horoscope. If you guessed that, you would be correct. I don't get the paper.

Belief in astrology reached a peak in the early 1600's, when techniques for predicting the positions of the planets were rediscovered. Thus we see many early scientists earning money through casting horoscopes.

“Like Kepler, Tycho stood with one foot in the past and was devoted to both alchemy and astrology. Like Kepler, he became a court astrologer and had to waste much of his time with the casting of horoscopes for patrons and friends; like Kepler, he did it with his tongue in his cheek, despised all other astrologers and quacks, and yet was profoundly convinced that the stars influenced man’s character and destiny though nobody quite knew how.”
(The Sleepwalkers, A History of Man's Changing Vision of the Universe, Arthur Koestler, p. 291)

I actual did an old-school search for the quotes above!

Mystic pseudo-science eventually gave way to true science as medical science began to provide demonstrable physical explanations for why we get sick. 

So what about the Rx symbol?!?!

Planets generally travel in one direction with respect to the stars. When a planets is on the other side of the Sun from us, the relative motion reverses and the planet appears to "flow upstream". When this happens, we say that the planet is in retrograde.  

In astrology, this is generally not considered a good thing. In particular, the astrological websites seem pretty unanimous about this being a particularly inauspicious time for surgery:

As an aside, this is a theory that could be quite readily tested, it would seem. Funny... despite the fact that the retrograde surgery problem is (apparently) well established in the astrological community, I am unable to find any direct tests of this. This is proof that the medical community is nefariously putting our health at risk strictly to make lots of money. Or maybe the lack of published research shows that the whole idea is preposterous nonsense.

Below we see a horoscope. I have circled two places where the symbol for retrograde have been used. The upper red circle shows the Rx symbol next to the symbol for Jupiter. The lower red circle shows the symbol for Venus with this symbol. This means that both Jupiter and Venus were in retrograde at this time. Rx is an abbreviation for "retrograde".

 Somebody's horoscope 
Thus, the Rx symbol is frequently found as part of the normal work that was performed by doctors around 1600. I haven't quite come up with an explanation for why astrologer/doctor/pharmacists picked this particular symbol to be the symbol for pharmacy. I will work on fabricating some sort of nonsense to explain that. In the mean time, if you are planning on surgery, avoid it when Mars or Venus is in retrograde.


  1. I greatly enjoyed the fascinating explanation of the retrograde symbol. However Rx is better understood in context of a long list of medical shorthands including Bx, Cx, Dx, Hx, Ix, Mx, Sx, Tx etc. The confusion is, perhaps, similar to that between the Rod of Asclepius and the caduceus.

  2. Thank you, Dr. Z.

    When I started digging into this, I was hoping to find a clearer connection. Maybe something like one of the early Renaissance physicians making a general statement like "When this or that planet is in retrograde, don't do bloodletting. Treat the patient with herbs instead." That would in effect say that if the horoscope has an Rx, use pharmaceutical means.

    Since I didn't find anything like that, I definitely think your explanation makes more sense!