How did the symbol Rx come to mean prescription? I’ve asked a couple of pharmacists and have only gotten shrugging of shoulders.
I used to know the exact answer to this. I vaguely remember it having something to do with the Latin god of medicine, who’s (Whose?) name I have also forgotten. It’s that one fellow whose (who’s?) staff was mixed up with some other god’s…These are the days I wish I had my Latin textbook on hand with its nifty list of gods and goddesses.
"No job’s too small, we bomb them all."
-Ace Wrecking Company
Shirley, I was sure that Unca Cecil wrote a column about this, but I can’t find it! 
I think that it was Latin shorthand, though, like Mr. Rogers says.
The Cat In The Hat
Not the Man, but his loyal and trustworthy minions.
Try the mailbag: http://www.straightdope.com/mailbag/mrx.html
Livin’ on Tums, Vitamin E and Rogaine
abbreviation for latin "recipe’.
[[Try the mailbag: "]http://www.straightdope.com/mailbag/mrx.html]]](http://www.straightdope.com/mailbag/mrx.html)
Thank you. In my research for that column, I found the history of the Rx symbol is a lot more interesting and complex than a simple abbreviation for recipe. And practically no pharmacists know about it. I even called two museums that specialized in the “history of pharmacy” and they didn’t know, either.
Jill
In medieval pharmaceutical notation, which used astrological symbols, the symbol for the planet Jupiter–which looked like a “24” ligature–stood for “to take.” With the vertical stroke on the left it looked like “Rx,” so it is to an extent, folk etymology.
Geez, Dougie, didn’t you read the wonderful article from the mailbag on this, mentioned by Manhattan in his post in this thread? In that article, Jill did a great job of showing that the Jupiter theory is only ONE of the accepted origins of the Rx symbol.
Do you have any proof that your belief about it is the CORRECT origin? 
I based this in part on two sources: Isaac Asimov in *Building Blocks of the Universe, and another book titled Exploring Chermistry, from about 1959. This book had a chapter on medieval chemistry and alchemy–the alchemists were trying to make gold from other elements, including mercury.
The Eye of Horus, I tell you!
[[Shirley, I was sure that Unca Cecil wrote a column about this, but I can’t find it!]]
Cecil Adams… JillGat… same difference.
(I’m just kidding!)